Pitbull people seem to think they can never have enough of these dogs. HOWEVER, when you have a dog pack, you need to be not only aware of dog behavior and individual breed traits besides taking into account individual dog personalities. Now I will use my dog pack as an example.
We have a Dogue de Bordeaux. They tend to have same sex dog aggression. They are very dominant, have a high prey drive and guarding instinct. They will not usually start a fight but will not back down from one. Due to the dominant personality of the breed, I selected members of the pack that would not challenge him. So when selecting our English Mastiff, I chose a female who had a confident personality. This also worked well with our Great Pyrenees who's breed can also have same sex aggression issues-she also has a calm laid back personality which works well in the pack. Our oldest dog is an Irish Setter. He is the perfect omega dog for the pack.