Using Stereo Receiver for rear Sonos channels

Hi...I have a Beam (V1) mounted under my TV for listening to video. I have my favorite old Pioneer SX-727 receiver for listening to music. How can I use the speakers wired to the Pioneer as my rear channels when listening to video? Is the Sonos Port product what will allow me to pick of the rear-L and rear-R channel, and plug them in as an Aux source on the receiver? (To be clear: Not trying to get audio out of the Pioneer into Sonos, only Rear channels out of Sonos into Pioneer.)  Thank you...Chris