Take charge when they are around. One way to do that is to try to involve them in activities around the house, i.e. cooking, baking, looking after your daughter, going to the shops, etc. If possible, give them different tasks at the same time so they are both busy but doing different things. It they start to annoy each other, try to split them up without being obvious - maybe twin 1 could go shopping with her dad while twin 2 hangs out with you, or vice versa.
Twins drive each other nuts by being together all the time, but can find it hard to be apart as they'll always miss each other and competitively wonder if the other one's got the better deal. It's like being married from birth,passionate and complicated! Try to get to know them as individuals and find out what they like/what winds them up about their twin, then build on that to help them get on better.
Other than that, the normal rules of parenting should apply - i.e. set limits, enforce consequences - if they break something, make them fix it, if they hurt each other, make them explain why and apologise, etc etc. And show them that you like and appreciate them when they do something good, and that they can set positive examples for your little one.
Keep in mind that teenage girls really need their dads and that they are probably struggling with all kinds of difficult feelings deep down about not living with him all the time and being 'replaced' by a younger sister. That might be one explanation for why they act out at your house - to get a reaction out of him. So the more quality time he can spend with them when they're around, the easier it might make all your lives long term.