Although I was able to successfully bi-amp as you wish to for years, I had an outboard crossover with level controls, the speakers were designed for bi-amping and I got lucky, as it took a few tries to find the right amplifier combination. So I have to agree with Tis49, you should use the same amplifiers if you're going to do it, or else get some amplifiers on loan that you could try it with. I also would not do it unless I had an external volume control/attenuator to match levels of the two amps. The gains in bass definition can be more than lost by the lack of coherence and difficulties in level matching.
