I used to not like the idea of one rabbit getting attached to another as well, Mimz! But from my experience, discussing this topic with others not personal experience, most of the bunnies “hang out” but do not become attached as they’re really not together that long. None of the people I know have had problems w/ depressed bunnies or bunnies that have become increasingly attached to each other. I think it may kind of work like my larger group, they become less attached to one particular bun and just seem okay hanging w/ everyone. Granted, I have not personally seen it, just what others who have done this have expressed to me from their experiences.
I know, Margo, Pres. of HRS, has her house rabbits all running together out as well. She has the same consensus as I do about these larger groups when I discussed my group w/ her. Also, Rabbitats does this sort of group set-up but rabbits are adopted not as a large group. Just some other things to think about that made me personally view them a little more positively.