Advice on Group Interview

Hi all. I recently had an interview with AmeriCorps and it went well. They called and said they wanted to do a second interview. I said yes and they told me it would be a 2 hour long group interview. I googled it and saw there are two kinds of group interviews, one with a panel asking you questions and one where they interview all the applicants at once. I am assuming it's the second choice since it's 2 hours long. Does anyone have any more info, tips or advice on group interviews? Thanks.