I have 4 roos right now (had 8). The 4 get along pretty well.
2 of the roos were raised together from chickhood
1 was introduced when he was about 4 months old to my BR roo. If my BR was not nice it could have gone badly, but he is a non confrontational roo. So, my BR roo accepted my 4 month old BLR wyandotte just fine and now that my BLRW is mature they still get along.
Just last week I put them all together (I had them separated as a banty flock and a standard flock) and they are doing amazingly well. They have established an order...BR roo is number 1 and he looks after everyone, BLRW roo is 2nd and gets in trouble with my BR for mating the wrong hens (but no fights ever break out, just running away from the aggressor), my phoenix mix roo is 3rd (my BLRW hates him) and my bantam cochin roo is last.
They have a wonderful dynamic and even though my BLRW hates the phoenix roo, they just keep their distance. Or I should say the phoenix roo stays away from my BLRW. Funny thing is my BR roo will break up any arguments between the BLRW and the phoenix, he always jumps in the middle of them when the phoenix is being chased. What a gentleman. He seems to strive for a calm, orderly flock. I just make sure that they all have room enough to run away from eachother if need be. (Since they are in runs and not free range)
now I have no idea what my BR roo had growing up, I got him at an auction so it's possible he grew up with other roos and that could be why he is so tolerant.
there's my roo story...it all depends on the roo's. I have had roos that WILL NOT get along with other roos at all and OEGB roos are pretty fiesty and I bet having more than 1 roo with that breed would be a task or a bloody mess.