Our two daughters, 12 and 16, share a room but they fight constantly and when they're not doing that they're moaning to us about each other. It would be best if we could separate them but at the moment that's simply not a possibility. I just don't know how to get them to be nice to each other, or even how to get them to leave each other alone. I feel the younger one goes out of her way to upset her older sister, but then I also know that the older one can be horrid to her sister. It's starting to feel like an impossible situation.