KRP, your first post stated that you "have" a 5-channel receiver; now this has changed to the 6-channel Yamaha 2200 which you might buy? Anyway, yes the Yamaha is one of the receivers that simply parallels its front channel amps when A+B is set. So, you can use the 2200 as mentioned in the previous reply(no separate speaker switcher is necessary)and despite the parallel operation when A+B is set, unless you play them at very high levels the 2200(which is a more substantial receiver than was implied in your first post)can probably handle the load without going into protection.
Since you'd have 6 rather than 5 channels of amplification, note that the A/B selection wouldn't be strictly necessary. If 6-channel stereo was set the dining room and kitchen speakers would get stereo, using 4 of the amp channels. The deck speakers would use the remaining front center and rear center channels(and would be silent when you set center front and back as "None"), but would get the combined output of the front left and right channels(i.e., mono)in 6-channel stereo mode. If acceptable this would avoid a possible(maybe unlikely)impedance problem with paralleled operation in A+B.
