have a flock of 25 with about 8 roos. It took quite a lot of flock arranging to get them all to get along without attacking. The best bet is to raise them all together from the start so they are friends and act brotherly to each other. if you have sweet non-dominant roos, they will usually get along together. If one acts up one day, do a confinement period, then sometimes he will fit right in after a brief removal. (Doing that makes the whole flock change their pecking order, so don't do it too much)
Once a rooster acts dominant and overly matey, that one will usually fight the other roos especially the other more dominant males. I love my freerange flock with all the roos working together, it offers lots of protection and watchful eyes for free ranging. I have systematically removed the dominant traits from the flock's males by selling the more agressive guys and i have only really sweet little roos who are tame as can be and brothers with each other. The hens are happier with a lot of non-dominant boys together, then with one huge dominant roo raping them all. They all have their little boyfriend and the boys don't stray much from their couple of mates. I hardl ever even see them mating, and with a dominant roo around, its pretty much all i ever saw! It has helped to have all the roos be of different breeds, since same breeds will 'gang bang' together and take over dominant spot in pairs. I don't know why but it is always the medium sized hybrid roos that I end up loving to keep. Small ones have 'little man' syndrome, and the larger ones try to dominate the flock. Size is everything, with males, it seems. heh.
The biggest roo in my flock was a polish, who no one would fight, but also he doesn't mate because his poof makes him essentially blind. that helped me out a bit, too, with getting them to submit to a blind but extremely large roo as dominant spot. after he died, (he layed down at the spot where one of my polish hens died and died there too, to go to chicken heaven to be with her i guess) they just continued being good boys.