We had a twin in our house, and her twin was in another chapter. I always got them confused, except when they were wearing their letters!
They had never been apart before college, both preferenced at the same houses, and just ended up in separate houses. They said it was the best thing they ever did, and they ended up living together their senior year--and had twice as many friends as everyone else! There were also twins in my rush group who ended up in the same house. I think it just depends. Go, have fun and keep an open mind, and it should all work out. Good luck!