Gracie -
Here is a really good thread written by a girl who also lived in a sorority suite while she was rushing.
http://www.greekchat.com/gcforums/sh...ad.php?t=22537
As you can see, she kept her options open even though she liked the sorority women she was living with.
The fact that you'll be living with women from 2 different groups is good - like everyone said they won't be able to talk about rush specifics with you. It will be helpful for you though as far as being able to go into the rush parties and see at least one person you know.