Sven,

that is how I currently run the same thing however, its very time consuming and gets out of hand with as few as 4 or 5 clans. If one clan wants to change moderators you have to add about 8 indicidual forum permissions. This gets to be a very annoying task.

I like the groups design. I'm just looking for an easier way to do this. Maybe assign a forum as "owned" by a group? Then only allow those group members permission instead of the other way around.