In a good collaboration,
no one should be missing out on their chance to design the robot. For a good example, let's look at the 2006 Niagara FIRST triplets. While I wasn't in FIRST in 2006, I've heard and talked about the Niagara FIRST triplets quite a bit. By my understanding, this collaboration did not go something like this:
1114: Hey 1503, 1680, here's the robot design. Get cracking!
Instead, it went something like this:
1114, 1503, 1680: Let's all work together! We'll design different parts of the robots individually, and then discuss our designs all together. That way, we all get a chance to "get our hands dirty" and we all get a superior product.
In the OP's case, collaboration is easier: they'll actually be in the same school. Remember, the more ideas you have, the better robot you'll build. The chances of stumbling on that "gamebreaking" or competitive design only increases with the number of people you have thinking about it (ie, look at the spread of the pinch rollers in 2010. They popped up most prominently as a result of the
148/217/1114, and 254/968 collaborations. The Pinch roller was generally accepted to be the best form of ball control that year).