Doug and Brian -- regarding my statement that the three of them "weren't a team" was merely in response to Tim's question -- not a comment on training techniques or anything else. I think it does take some "practice" for any group to become "a team" regardless of how well they have been trained. (Just ask any All Star coach!) But for the purposes of training, it actually may be a teaching advantage for the students NOT to have much experience diving together.
Doug -- I'll have to bow to your greater experience in technical diving situations regarding the advantages/disadvantages of having experience diving together. In my very limited experience in both technical training and techreational diving, I've found that having a good idea of my teammates' strengths and weaknesses, both physical and mental, (and we all have both) is just one more "team resource" that is good to know and use. At least in my life experience, we only learn these strengths and weaknesses when we "play together" as a team (and this is true for any "team sport") -- but perhaps you are right here. I hope I'm never in a situation where I need to find it out.