Male Ferret now trying to mate with other males?

We recently had 11 baby ferrets, and at about 2 months we had to put them in with the 4 other adult ferrets because there was no longer room for them in their hutch. The "alpha" male in that group of course tried to mate with the females, but as i was obviously annoyed about it, i separated him from the others. All of the female (babies) were then sold quite recently so i put him back into the group. Instead of trying to mate with the adult females, he tried to mate with one of the male babies, resulting in a lot of blood! I separated him again because i don't want him hurting the other ferrets like that. We do not plan to sell all of the babies but i don't want this happening again. I know its common and fairly normal but it hurts the other ferrets a lot. I don't want to have to sell the alpha ferret either. Is there anything i can do to train him into not doing this or even just deter him? Getting him done is too expensive an option right now, and i feel bad having him continually on his own.