^ What AZ said.
Seriously, if the "Leaders" are deciding who joins a group and who doesn't, then if someone doesn't get into the group they wanted they'll feel left out or whatever. That's a great way to start arguments if you ask me. I like the idea in general, but I'd rather the groups just be open for anyone, but you can only be in one group at a time.
Also, if the leaders can decide to kick someone, they can kick people because they didn't like them or something. I think that only the Moderators should kick people from groups, and they better have a very good reason for it too. Maybe the mods should run the groups the whole time instead of electing group leaders from everyone on the board?