I have a Yamaha dspA1. I have prewiring for 10 or 12 speaker sets all over the house. How would I be able to hook up these other speaker sets through the receiver? I would like to be able to select one speaker set at a time (don't want them all running at the same time!)...do I need to get some kind of selector box? Where can I find something like this? Also, anyone know where this should be plugged into the receiver? Any help would be MUCH appreciated. Thanks a lot!