I've almost always housed my buttons in a group. I had one pair that was the exception. My current group/setup is actually the best that I've ever had, including better than the pairing. I have five hens and three roos in the group. They're in a playpen converted into a cage. I have no feather plucking, no fighting (some dominance between one of my higher roos and the bottom roo, but no actual fighting), and all around, basically no issues. They huddle together and sleep in a clump of bodies at night. When I had groups before, my main issues were feather plucking. I think that was mostly because of spacing issues though.
I keep all of mine together without problems. It may not be reccomended, but its working great!! They all look happy, and noone has gotten picked on yet....