Sims 3 Xbox 360: Is there a way I can move out ONE Sim only or make a Sim's girlfriend move in?

I have a family of 4. Father, Mother, Son, and the Dad's older brother. The older brother has a girlfriend and no kids. He just aged from young adult to adult. Can I move the older brother into his girlfriends house or can I get the girlfriend to move into my families house? Also if yes, how can I do it?