nashuasteve, assuming that you are using a typical 4 channel receiver (front/rear and left/right) to drive the speakers, you can use the fader control on the head unit to select between two 'zones', without any additional switch. For example, wire the cockpit speakers up as left and right REAR and wire the cabin speakers as left and right FRONT. Then, to play music only in the cabin, adjust the fader to 100% front. 100% rear would play only in the cockpit. I plan on adding a pair of speakers in the salon and will wire it up exactly this way.
