Route movie audio to a different Android device - is this even possible?!

[AC Question]

I have an Android HDMI TV dongle connected directly to a projector. Audio is output to the projector's internal speakers.

Is there any way (or app) that will allow me to route the audio to another Android device (while watching a movie for example) that I can then connect to my sound system?

Final result would be: video output through projector; audio output through sound system.

Thanks!