I would let him have his existing girls with him and try to keep your two new ones away for at least another month or so. It is still breeding season for these ducks and some of them can be really rough on the younger ones. If he ends up being too much trouble then I would rehome him unless he is very special to you. Good luck with your decision. I kept my female Call Duck away from the drakes for almost 5 months and all was fine but the whole time they could see her and her mate and not touch them. Welcome to BYC as it is a wonderful site where we all try to help each other.And should I only separate him or him with his existing girls?