New receiver biamping question

[Maggot]

I just upgraded from an older Marantz SR7009 to a SR7013. My old setup was a basic 5.1 using the biamp function in the receiver and it's surround back amps.

Now I have a 5.1.4 height setup, but since the surround backs are no longer assignable in this model, I can only use HEIGHT 1 or HEIGHT 2.

Question....will this work: if I choose say the 7.1 biamp config in the menu, which would use the HEIGHT 2 amp to biamp the front L/R stereo music, would there STILL be a signal at the HEIGHT 2 pre-out for going to an external to run the rear heights?

I mean....right now, without biamping, I am using all 9 amps to run my 5.1.4. But.....I am just not sure about the possibility of using the HEIGHT 2 for biamp, having those speakers cables in that port, BUT using the pre-out HEIGHT 2 signal to an extrernal amp? Would that even work?

Would it just be better to buy something like the Outlaw Audio 5000 5ch amp and pre-out from the receiver using Y-splitters to get biamping completely from that external while the receiver just handles the 4 heights and two surrounds?

Basically........can one use the HEIGHT 2 assignable amp for biamping, YET still have a HEIGHT 2 signal at the pre-out for when one is in surround theater listening