Pi surround sound/multi room

Hi guys, this is my first post. I’m slowly gathering knowledge of the little wonder that is the raspberry pi.
I have successfully put together a hifi pi (zero) with a phat dac that is connected to my hifi separates system. I use it every day to stream with AirPlay, oh sorry, AirPi. I am hoping to one day expand this as a pi controlled “sonos” type wireless multi room system. I also have a pi2 running retropi, this stays connected to my tv for hassle free retro gaming and kodi playback.
I have a question that I hope someone could help me with. Is it possible to use the retropi (that is near the tv) to send surround sound/audio signal wirelessly to the hifi pi? To be played through my hifi. Not just for gaming, but for whatever is going through the tv. So using the audio out of the tv I guess as opposed to just whatever audio is coming out of the pi which would be gaming or Netflix etc.

Thanks in advance, any help or pointers would be much appreciated.


I have a suggestion. Dump your proprietory hardware and use your (hopefully) existing audio system and FM tuner.
Buy a $5 FM transmitter module from AliExpress which has an audio USB codec built-in.
Set up a pi zero, or similar to drive the codec, fetch mp3 tracks from a solid/hard disk, has apache which serves html pages to select tracks and controls the system.
Cost - neglible - Fun - immense. Look here for an overview: Audio Distribution System