Funny things, Kribs. I had a small group to get a pair, there was a fight and 2 didnt make it. I too ended up with 1 female and 2 males. I too thought it would be alright as they are in a 340, plenty of space for the two males to establish as their own, and the female can pick. She eventually picked the larger of the two, and had one lot of fry. About two weeks past the fry hatching, she killed him. The fry were subsequently eaten by the remaining male, before they had a batch of their own. Same thing happened, 2 weeks later, found him at the bottom too, no signs of illness. I can only assume she killed him too.
I picked her up a new mate at a LFS yesterday, over 3" so much larger than the first two, and her, im hoping this isnt going to be an ongoing thing.
I generally find the females are the ones that do the majority of the nipping etc, so i imagine removing her wont stop the male being agresive with the others, unless its because they have eggs somewhere.