Sam:
I honestly don't know. My group interview ended up being 2-on-2. So, my fellow interviewee and I didn't have a group-oriented question. It would be a little awkward with such few people! (I did notice one of my interviewers looking at me while my fellow interviewee was talking. I guess she did this to check out my body language or something. I am not sure.) However, you are right. The idea of group interaction is very important to the school in general as well as during the interview.
Sam, I don't think too much emphasis is placed on the interview. I believe it is important, but since it is relatively easy (at least, according to most of the people I talked to on my interview day) I think it's difficult to effectively use it as a way to guage applicants. Yes, I know, some applicants can't communicate very well. But, generally speaking, I think the interview is not so bad. In fact, I've encountered a few people who had "okay" interviews and were still accepted. However, good interviews can only help you. Right?
I am just expressing my opinion. I hope I sound reasonable. Take care, Sam, and all else who find this forum helpful.