If you want stereo, (distinct left & right channels), in each room, you can also use your Multi-Channel setting.
Your TX-NR636 is a 7.2 receiver... that means you have 7 speaker outputs plus 2 subwoofer outputs. Your 7 speaker outputs are split into 3 pair, plus 1. The 3 pair are: Front Left/Right, Surround Left/Right, and Rear Surround Left/Right. The Plus 1 is your center channel.
Your Multi Channel setting sends the left stereo channel to ALL your Left speakers, and the right stereo channel to ALL your Right speakers. So you can have 3 pair of Stereo outputs.
Left & Right to one room, Surround Left & Surround Right to another room, and Rear Surround Left & Rear Surround Right to the third room. Your receiver lets you set the volume of each speaker individually, so you can balance the speaker pair in each room. Once you get the individual speaker volumes set, the master volume on your receiver/remote will control each room together, just like it does now w/ your Mono Movie.
At least this way will give you stereo in each room, instead of mono.
By the way, other companies also have their Owner Manuals online instead of hardcopy in the box. It does not make them "jerks".