(Post edited...)
Cool thanks, that's very helpful. I will mess around with this and see what I can do.
Also related (and what originally had me wondering if nesting repeaters was possible) is that the method described in the tutorial, aka just using ${project.projectMembers}, does show a list of projectMembers, but displays their UUIDs rather than their names. Further down in the tutorial, after setting up edit mode binding, the names of the children do show up when in edit mode, (making selection much easier than having to pick UUIDs) but then switches back to a list of UUIDs display when exiting edit mode into just "view" mode.
I thought, naturally, the answer would be to just replace the template expression I mentioned above with ${
project.projectMembers.name} but that doesn't work because project.projectMembers is a list and not a single object, thus it doesn't automatically iterate through the list and display their names (even though it does automatically iterate through the list to display UUIDs...) :-P
Thinking about this led me to figuring out using something like the "each" and "print" built-in functions, and then further also to asking the original question above about nested repeaters... but now my question would be: is there a sanctioned way to do one of these methods that still works with the Edit Mode Binding system? AKA can I display a list of children objects with more than just their UUIDs that will still work when switching to edit mode? I will certainly experiment on my own but am curious if there is a "right" way to do it even if I discover a way that kinda works, or appears to work but may actually cause problems down the road.
And maybe I just screwed something up in the tutorial and my ${project.projectMembers} should actually be displaying names in both "view" and "edit" modes. Either way thanks for your help and I will report back if I discover the obvious answer to editing relationships with multiple children through a Dynamic Output Element using "Interactive Mode" and always showing the name instead of the UUID.
-Pete
(Redundant explanatory rambling language above is mostly for search indexing purposes, sorry!)