If I understand you, the goal is to run the same signal to the rears (surrounds) as to the main speakers. Doing that through wiring (either by splitting the pre-amp outputs, using an A/B speaker system such as that found on some receivers, or using the second zone for the surrounds) will prevent you from using the surrounds as surround speakers for other sources.
Here's a suggestion that might work well for you while also allowing you to have normal use of your surrounds: the 950's 5 Stereo mode. It will operate with your center as well as the fronts and surrounds, but aside from that it is going to behave the same as wiring your surrounds up to get the same signal as the fronts - and without complicating your cabling. It will work with any stereo analog or PCM digital source.