That's always a tough one, and sometimes it's very hard to break them of it. You can start by feeding her last, and at first feed her from your hand, so she knows she has to rely on you for the food. Make her work for everything, even affection. Make her sit before you pet her and so on. Give her a toy and then take it away. She may even growl at you, but what I do, and we have a girl I am working with right now and she is getting better at it, is when she growls when I try to take a toy away I quickly grab her by the side of the neck and tell her NO, then I take to toy away. It takes time and patience, but you can start with this. Try to watch her with the others so they will not fight, as the fights could get worse. Plus I would not leave them alone together when you are not there. I would crate them or at least her. You may be doing this already, I don't know. Keep us posted on her progress.