King,
The interview process was a little nervous for me because I am better with a one on one interview format. The best thing I can say to you is to be prepared! During my interview, all that I prepared for was sidetracked by a question that I wasn't prepared for.. What I thought of the Dr. Kevorkian's televised euthenization of a patient on national TV.. Man that was a hard one especially when I didn't even watch it. But it's not the fact that I watched it that mattered.. It's how I felt about it.
That was an uncommon question, however be prepared as much as possible. Then you won't sweat the uncommon stuff. It is also very important that you speak in a way that will make the interview committee remember you. Don't leave anything uncovered, your research, extra curricular activities. If they don't ask you, try and find a way to bring it up.. Politely of course, this is a group interview. I personally don't like group interviews, I don't know how much the benefits outweigh the negatives, but I know that they must have their reasons..
Good luck,
Duke