With the two integrated amps you mention you can only do passive bi-amping with speakers that are designed to be bi-amped. I believe you should be able to connect all of your sources to one amp then use the preamp outs from that amp and connect those to one of the inputs of the second amp. You can then connect the speaker outs of the first amp to either the low or high inputs of the speakers and the second amp to the other speakers inputs.
You would need a different preamp/amp set-up in order to use an active crossover and unless you wanted to add subs to your system, it's probably not worth doing.