Hi there,
Yes, it's technically possible if you have preamp outputs on your receiver. Ideally, you would want to use four identical amplifier channels to bi-amp one pair of speakers. Since your amps would be different (two channels in the receiver, two in the external amp), you might have some integration issues. That said, if you hook everything up properly, yes, it will work. Experiment around with it and see if you like it.
Good luck.