Perhaps Chris, JohnK or another smarter-than-me guy can answer this....aside from an active crossover, is it possible to design a three-way passive crossover, but in two completely separate units?....say one part to the tweets and mids and the other part isolated for the woofer so that two amps could be used in bi-amp fashion. I guess this would be like having a two way speaker with a single crossover, and a woofer (in the same cabinet)with it's own low freq pass or something similar, and each having it's own amp supply.

Half of communication is listening. You can't listen with your mouth.