The DEP selection is exactly as described in the first few posts on this thread, save that, and I have this on reliable information, the group exercise now involves a scenario whereby a ground service Co. has £250 K to spend and each member of the class has to present a business case (contained in an A4 sheet in front of him or her) as to how the money should be spent. There's little point in going into any further detail of each business case since the purpose of the exercise is to assess interaction not 'how to spend £250k.'
No useful tips to dish out, except the obvious: work as a team, don't stick out unnecessarily, justify your arguments, be prepared to change your mind, listen, communicate and dont be heard to be saying what a silly game it all is.