Male guppy attacking other male guppy? Please help?

So I have two male guppies from PetSmart and they were in the same tank together. One is slightly larger. The yellow one (larger one) will bully the smaller one, which is orange. The yellow one hangs out with the females (there are four females) and ignores him, but the girls seem to want to hang out with the orange one as well and will swim up to him and try to get him out of his corner. What can I do about this? Thank you