About leaving, can you enforce people not leaving? Walls, rules etc.? Sounds stupid/obvious maybe. And of course that's not for everybody, but that's how we do it, if you're here and agree with the rules, you're stuck with us. And merging happens, we have people who merged because they specifically wanted to in that unit, or it was the most natural thing for them; that has nothing to do with anyone else. Some people are just better off as one. I wouldn't worry about it.