It wasn't ideal but when the 'canes came through and we went without power for several weeks I had to consolodate and I had a two pairs of Oscellaris and a pair of Clarkii's in the same 55 gallon. There is a thread here somewhere. All were mature pairs, the tank housed one Oscellaris pair previously. I had no issues, which I really didn't expect since I had all of them for a few years and they were relatively peaceful fish.
Before it was all said and done, I also had to put a tomato clown single in there because it was getting bullied badly in the other larger tank and still peace prevailed. The tomato made me nervous because it was a nippy fish, and had nailed me a few times when I got into it's space.
Everyone had their space and at feeding times, they just fed and returned to their territories.
Again, this wasn't ideal. I had to reduce 6 tanks down to two so that we could keep them running with a generator. These two tanks were overstocked and while some of the fish got out of hand, the clowns were all peaceful. We were also doing almost daily water changes to keep things stable, especially considering that we were forced to use tap water.