I think it depends. I've kept a group of 2.3 Tigers together. I strongly believe that only one of the females is mature, but both males are mature. There is the ocassional small bite on the immature females, but for the most part they focus their attention on the big girl. That said they have a lot of space to get away from each other. I think that males are able to tell if a female is receptive or not. I might worry more about a male that is just becoming mature and not quite sure what he is doing yet 
