For reference, I've reposted most of the initial schema at the bottom of this email. Of course, that doesn't mean we have too. I don't know how people are going to use the system. I didn't want to design in too many static assumptions about how data would be related. I'm just trying to create a flexible schema.
Group is obviously too vague a word.
My idea was that there would be groups of groups for creating a heirarchical organization of people. This would leave the door open for adding new relationships that I haven't yet envisioned. PostGreSQL's class inheritance could handle this quite well. Group, Suite, and Project tables would all inherit from the base container schema. The container table would then contain all projects, groups, and suites.