Newbie question re: remote speaker wiring

I have a Yamaha RX-V1 receiver that is being used as a A/V preamp, running into a 5 channel power amp in my great room. I'd like to hook up a set of speakers in another room and want to take advantage of the unused amps in the receiver.

Would it hurt anything to hook up the second room speakers to the Speaker B terminals of the receiver, even though I am tapped into the Main Out terminals? My understanding is that I could turn the second room speakers off and on with the front panel toggle, but the source would be the same as the main room. Not necessarily looking for an autonomous Zone 2 at this point. Just would like to avoid blowing up my receiver. :-)

There are Zone 2 outputs which are line level only, so the other thought was to buy an inexpensive power amp for the second room. Thanks in advance for any input you may have.