I stumbled across this little exploit by accident. Not sure how useful it really is but I figured I'd post it and see what the community could do with it.
1. Waitlist for groups you want to get in.
2. Create a premade group of your own.
3. When you get invited to the other group you basically take control of the person's oque group and it becomes yours. (Name changes to your group name and what not)
Cheers!