diff --git a/spec/Section 6 -- Execution.md b/spec/Section 6 -- Execution.md
index 3bc9d7a94..9dded7c5d 100644
--- a/spec/Section 6 -- Execution.md	
+++ b/spec/Section 6 -- Execution.md	
@@ -857,10 +857,15 @@ and so that fields are grouped according to the set of deferred fragments that
 include them.
 
 Information derived from the presence of a `@defer` directive on a fragment is
-returned as a Defer Usage record, unique to the label, a structure containing
-only:
+returned as a Defer Usage record, unique to the label, a structure containing:
 
 - {label}: value of the corresponding argument to the `@defer` directive.
+- {ancestors}: a list, where the first entry is the parent Defer Usage record
+  corresponding to the deferred fragment enclosing this deferred fragment and
+  the remaining entries are the values included within the {ancestors} entry of
+  that parent Defer Usage record, or, if this Defer Usage record is deferred
+  directly by the initial result, a list containing the single value
+  {undefined}.
 
 A Field Group record is a structure containing:
 
@@ -943,7 +948,13 @@ parentTarget, newTarget):
     - If {deferDirective} is defined:
       - Let {label} be the value or the variable to {deferDirective}'s {label}
         argument.
-      - Let {target} be a new Defer Usage record created from {label}.
+      - Let {ancestors} be an empty list.
+      - Append {parentTarget} to {ancestors}.
+      - If {parentTarget} is defined:
+        - Let {parentAncestors} be the {ancestor} entry on {parentTarget}.
+        - Append all items in {parentAncestors} to {ancestors}.
+      - Let {target} be a new Defer Usage record created from {label} and
+        {ancestors}.
       - Append {target} to {newDeferUsages}.
     - Otherwise:
       - Let {target} be {newTarget}.
@@ -978,7 +989,13 @@ parentTarget, newTarget):
     - If {deferDirective} is defined:
       - Let {label} be the value or the variable to {deferDirective}'s {label}
         argument.
-      - Let {target} be a new Defer Usage record created from {label}.
+      - Let {ancestors} be an empty list.
+      - Append {parentTarget} to {ancestors}.
+      - If {parentTarget} is defined:
+        - Let {parentAncestors} be {ancestor} on {parentTarget}.
+        - Append all items in {parentAncestors} to {ancestors}.
+      - Let {target} be a new Defer Usage record created from {label} and
+        {ancestors}.
       - Append {target} to {newDeferUsages}.
     - Otherwise:
       - Let {target} be {newTarget}.
@@ -1033,31 +1050,84 @@ BuildGroupedFieldSets(fieldsByTarget, targetsByKey, parentTargets)
         - Let {fieldDetails} be a new Field Details record created from {node}
           and {target}.
         - Append {fieldDetails} to the {fields} entry on {fieldGroup}.
-    - Continue to the next entry in {targetsByKey}.
-  - For each {key} in {groupDetailsMap}:
-    - If {IsSameSet(targets, key)} is {true}:
-      - Let {details} be the map in {groupDetailsMap} for {targets}.
-      - Let {newGroupedFieldSet} be the corresponding entry on {details}.
-  - If {details} is not defined:
-    - Initialize {newGroupedFieldSet} to an empty ordered map.
-    - Initialize {shouldInitiateDefer} to {false}.
+- Initialize {groupDetailsMap} to an empty unordered map.
+- For each {maskingTargets} and {targetSetDetails} in {targetSetDetailsMap}:
+  - Initialize {newGroupedFieldSet} to an empty ordered map.
+  - Let {keys} be the corresponding entry on {targetSetDetails}.
+  - Let {orderedResponseKeys} be the result of
+    {GetOrderedResponseKeys(maskingTargets, remainingFieldsByTarget)}.
+  - For each {responseKey} in {orderedResponseKeys}:
+    - If {keys} does not contain {responseKey}, continue to the next member of
+      {orderedResponseKeys}.
+    - Let {fieldGroup} be the Field Group record in {newGroupedFieldSet} for
+      {responseKey}; if no such record exists, create a new such record from the
+      empty list {fields} and the set of {parentTargets}.
+    - Let {targets} be the entry in {targetsByKeys} for {responseKey}.
     - For each {target} in {targets}:
+      - Let {remainingFieldsForTarget} be the entry in {remainingFieldsByTarget}
+        for {target}.
+      - Let {nodes} be the list in {remainingFieldsByTarget} for {responseKey}.
+      - Remove the entry for {responseKey} from {remainingFieldsByTarget}.
+      - For each {node} of {nodes}:
+        - Let {fieldDetails} be a new Field Details record created from {node}
+          and {target}.
+        - Append {fieldDetails} to the {fields} entry on {fieldGroup}.
+  - Let {shouldInitiateDefer} be the corresponding entry on {targetSetDetails}.
+  - Initialize {details} to an empty unordered map.
+  - Set the entry for {groupedFieldSet} in {details} to {newGroupedFieldSet}.
+  - Set the corresponding entry in {details} to {shouldInitiateDefer}.
+  - Set the entry for {maskingTargets} in {groupDetailsMap} to {details}.
+- Return {groupedFieldSet} and {groupDetailsMap}.
+
+Note: entries are always added to Grouped Field Set records in the order in
+which they appear for the first target. Field order for deferred grouped field
+sets never alters the field order for the parent.
+
+GetOrderedResponseKeys(targets, fieldsByTarget):
+
+- Let {firstTarget} be the first entry in {targets}.
+- Assert that {firstTarget} is defined.
+- Let {firstFields} be the entry for {firstTarget} in {fieldsByTarget}.
+- Assert that {firstFields} is defined.
+- Let {responseKeys} be the keys of {firstFields}.
+- Return {responseKeys}.
+
+GetTargetSetDetails(targetsByKey, parentTargets):
+
+- Initialize {keysWithParentTargets} to the empty set.
+- Initialize {targetSetDetailsMap} to an empty unordered map.
+- For each {responseKey} and {targets} in {targetsByKey}:
+  - Initialize {maskingTargets} to an empty set.
+  - For each {target} in {targets}:
+    - If {target} is not defined:
+      - Add {target} to {maskingTargets}.
+      - Continue to the next entry in {targets}.
+    - Let {ancestors} be the corresponding entry on {target}.
+    - For each {ancestor} of {ancestors}:
+      - If {targets} contains {ancestor}, continue to the next member of
+        {targets}.
+    - Add {target} to {maskingTargets}.
+  - If {IsSameSet(maskingTargets, parentTargets)} is {true}:
+    - Append {responseKey} to {keysWithParentTargets}.
+    - Continue to the next entry in {targetsByKey}.
+  - For each {key} in {targetSetDetailsMap}:
+    - If {IsSameSet(maskingTargets, key)} is {true}, let {targetSetDetails} be
+      the map in {targetSetDetailsMap} for {maskingTargets}.
+  - If {targetSetDetails} is defined:
+    - Let {keys} be the corresponding entry on {targetSetDetails}.
+    - Add {responseKey} to {keys}.
+  - Otherwise:
+    - Initialize {keys} to the empty set.
+    - Add {responseKey} to {keys}.
+    - Let {shouldInitiateDefer} be {false}.
+    - For each {target} in {maskingTargets}:
       - If {parentTargets} does not contain {target}:
         - Set {shouldInitiateDefer} equal to {true}.
-    - Initialize {details} to an empty unordered map consisting of
-      {newGroupedFieldSet} and {shouldInitiateDefer}.
-    - Set the entry for {targets} in {groupDetailsMap} to {groupDetails}.
-  - Let {fieldGroup} be the Field Group record in {newGroupedFieldSet} for
-    {responseKey}; if no such record exists, create a new such record from the
-    empty list {fields} and the set of {parentTargets}.
-  - For each {target} in {targets}:
-    - Let {fields} be the entry in {fieldsByTarget} for {target}.
-    - Let {nodes} be the list in {fields} for {responseKey}.
-    - For each {node} of {nodes}:
-      - Let {fieldDetails} be a new Field Details record created from {node} and
-        {target}.
-      - Append {fieldDetails} to the {fields} entry on {fieldGroup}.
-- Return {groupedFieldSet} and {groupDetailsMap}.
+    - Create {newTargetSetDetails} as an map containing {keys} and
+      {shouldInitiateDefer}.
+    - Set the entry in {targetSetDetailsMap} for {maskingTargets} to
+      {newTargetSetDetails}.
+- Return {keysWithParentTargets} and {targetSetDetailsMap}.
 
 IsSameSet(setA, setB):