oh I LOVE group interviews
put me in that situtaion and I'll be a show off and confident as hell
put me in a one 2 one interview and I feel underpressure and clam up.
Basicly, the interviewers (there will probably be a few observing) will be looking for 1) confidence 2) your ability to work as a team, which is oretty much the point of putting you in a group interview situtaion.
If you are naturally shy, then try yur hardest to convince yourself to be bright and confident for those few hours BUT don;t come across as annoyingly loud and obnoxious, I reckon that would be just as bad as not saying a word! so find a balance.
In every group interview I've had part of it was breakign off into teams discussing a set topic then presenting your findings (or maybe a role play)_ to the rest of the group, and the interviewers are walkign round observing your discussions. Make sure you come up with some ideas and make a point of asking the others what they think of them and any ideas of their own and praise whatever they come up with.
When you are presenting your role play or whatver, again make sure you come across as pleasant and confident, speak clearly and smile.
I'm the shyest person you could ever meet, but for some reason in thee group interviews I'm like a brand new confident person, wish i was like that all the time