Dave Cormier's blog post "Cheating as Learning" is a great primer on peer learning. He writes:
I want you to cheat. I want you to ‘get the answer’ from your neighbour. I want you to tell me that you did that...if you take anything from this course, is that making meaning, creating knowledge, is something that happens in public.
Especially for groups who have spent time in traditional classrooms and being tested, it's important to emphasize that it's encouraged to reach out to your peers, as they may default towards working alone and not sharing resources/opinions.