Another option is to add a small second power amp to your setup and either split the pre-amp output with a Y-adapter or, as in the case of the McCormack, use your second set of pre-outs to go to the second amp.
If you look around on the used sites you can probably find a small power amp good enough for kitchen speakers for less than the price of a switch box that's high-enough quality to keep from degrading the sound of the whole system. I got a nice little used Yamaha amp for $85 at a local dealer and it works very nicely
If you look around on the used sites you can probably find a small power amp good enough for kitchen speakers for less than the price of a switch box that's high-enough quality to keep from degrading the sound of the whole system. I got a nice little used Yamaha amp for $85 at a local dealer and it works very nicely