Housedoc, I concur with XenonMan. You want to make sure that the selecter does "impedence matching" so as to avoid the resistance problem noted by XenonMan. In fact I use a 6 zone speaker selector from Phoenix Gold. It is a simple switch that I use for 1 to 4 rooms simultaneously (kitchen, dinning room, living room, and office). It runs off of 2 channels from my Outlaw 7700 with 2 Jamo 60 watt speakers in each room. This has been hooked up and used for more than 3 years. The 7700 never even gets warm when I have my main system on (as noted in my signature) as well as all 4 rooms--even when I crank the volume when the wife is not home! Therefore, I don't think you will have any problem.

As a side note, I blew a speaker (a previous post about 15 months ago) before my 7700 even got warm!