Y-split vs separate cables

Hi- I have a marantz 8802a which offers the ability to bi-amp my front speakers via 4 xlr puts. However when you do that the processor makes you give up another channel in my case it’s he surround back speakers ( even though there are 13 connections only 11 can be used. Pretty lame). At the moment I don’t mind as I prefer the speakers being bi-amped (revel studio 2) since I have extra channels on my lexicon rx7 amplifiers and I’m changing around the room so back speakers aren’t connected.  Curious if I had audioquest make a y-split cable what that does to the voltage and other specs (on which I’m not an expert) of the signal from the processor to the amps. Fronts are crossed over around 100 hz as I have dual subs. If I used the split cable I could continue having bi-amped speakers while also being able to then run the full 7.2.4 surround.   ANy thoughts appreciated. 
sounds like lots of wheel spinning
Interesting view I suppose.  I’m interested in the actual effects of runnning a split cable vs using dual outputs. Maybe there is no bad outcome which would be great as I can do what I want while not having to upgrade to the 8805. 
I have the same dilemma when I upgrade to an Anthem AVM-60...They (Anthem) don't support bi-amping and they suggested using a splitter. However, the voltage out would be half per channel IF the cable is PERFECTLY balanced. Granted, if the front end of the amplifier is sensitive enough it could overcome the loss of the voltage/signal. 
In my limited knowledge, I would think, separate channels would produce the best overall sound. 
If you double the speakers on one set of outputs, you halve the impedance. Not a huge deal as long as your amp is stable.