Traveller,

I like PJ's idea of the 2 tandems and a solo with the switching around paddling partners. The solo probably wouldn't keep up with the tandems, but in a group setting with everyone rotating I think things would stay pretty even. It would be a great opportunity for everyone to develop strong skills in a solo, plus it gives you an extra boat for the fishing days and more room in the tandems.

Those are just my thoughts on the matter.