Multiple includes inside main justfile

[komandar]

Hello,

we are currently using just for some of our projects.
For this we would like to use as we have always done before with makefiles the inclusion of other make or justfiles. Here as an example:

primary justfile inside root folder:

include <folder/project-a.just>
include <folder/project-b.just>
include <folder/project-c.just>

@cmd1:
	@printf "Output something..."
[...]

In the individual project justfiles there are further commands and also constants with a unique identifier.

Is this currently already possible with just?
I only found the include function which allows to include only one file in a just file. Also the parameter "--unstable" prevents us from using this actively in our projects.

Thanks for your help.