BuddyPress.org

Should be quite easy to do. When someone creates a group you give them the choice of what kind of group it should be using the groups api. This you attach to the group as groupmeta. Once that is done you can enable functionality based on that meta data. Have a look at the group api docs in the codex

The way I did it was a bit different and I never got round to making a plugin out of it. It was for a personal site, which i haven’t got to for the last 4 months or so. Too much client work…