I just wanted to chime in here and say that as far as I can tell, the entire groups API under OpenACS 4 is a mess. Maybe it's just me, and maybe it's the documentation, but I've spent a lot of time over the last month trying to figure out how to create groups, assign users to groups, and create various relationships -- and every time I think that I've figured out what's happening, I discover a new problem.
Don't get me wrong: I think that the theory behind composition vs. membership relations is a brilliant one, and it could be that I just require a bit more documentation to know what's happening. But if the dotLRN team is working on a new system for working with groups, this will be a big step forward for the usability of OpenACS.
