Is it possible to run the balanced outputs from the surround processor into one set of the analog preamp's balanced inputs and then simply make sure the volume control on the analog preamp is always set at the same volume?Yes. what volume you choose depends on your situation. I would suggest something easy to remember - such as 12:00 if you have a rotary dial. You want to also be careful that you don't pick a volume level such that if you inadvertently switch to another input it risks blowing your windows out (or worse your speakers). Finally you need it at a level within the parameters of your HT setup adjustments.
I frankly think this is the most convenient solution short of a built in HT passthru. It worked great for me.