aftermarket radio installation - need a little help!

I bought a Clarion DXZ545MP to replace the factory cassette deck in my '93 Quest. I also bought a wiring harness so I don't have to cut off the factory plugs. However, I noticed that there is one two-wire plug that I don't have an adapter for. After a little testing, I found that it is the wires that allow you to control the radio from the backseat. The headphone jack still works without the wires connected, and I know that I will lose the functionality of the scan, volume, etc. buttons from the backseat, but the radio has a remote control, so it really isn't that big of a deal. What hurts is that I lose the functionality of being able to only listen to the headset so the rest of the speakers are off.

My real question is the clarion DXZ545MP has a 2 zone setup, so I am wondering if it is possible to be able to hook it up in such a way that I can hit the zone button and only sound coming out of the headset would work so the rest of the speakers would be off? Any help is appreciated.