Adding 2 extra channels to pair a MC7205 with a...

Question

I'd like to move my MC7205 into my theater and pair it with my MX-119, but I'll need an extra 2 channels of power to run the 7.1 feature.  Is adding another stereo amp to the Mx-119 pretty straightforward, or is there something I should be mindful of?  Can I connect the MC7205 to the MX-119 using the serial cable and then use RCAs to connect the other two channels, or will that mess with something the wrong way?

Thanks