Speaker A / B
I think any receiver with the speaker A/B terminals should work. In the case of my Yamaha HTR-5860, you specify in the configuration whether the B speakers are in the same room or a different location. If they are in "the same room" than the center, surround, and sub channels remain on. If they are in "different rooms" than the receiver turns off the center, and surround, and sub and only sends sound to the B speakers.
A zone 2 receiver would work, but is only necessary if you want to run the stereo speakers at the same time as a 5.1 system in different rooms.
For 2 channel, you might also look for a receiver with a "Pure direct" mode which can disable the display, video circuitry, and audio processing, when playing an analog source.