Agree with the above, I've found it best to learn the material on my own, then pair up with one or two people to review. A group bigger than three has been distracting for me. I've found that the best way for me to study was to find someone who has the same learning style and learns at the same pace as me. When I've studied with someone who was not my match academically I found it frustrating because one of us was always dragging the other along. For the MCAT I had a great study buddy, he knew the physical science really well, I was good at reasoning and test taking logic. I think we really helped to fill in each others gaps and both kicked a$$ on the test