iMac multiple independent audio outputs

I have a Late 2015 iMac 27" Retina 5K. I am also using a Mini DV to HDMI adapter to run a Sony TV as a second monitor to extend my desktop. What I am trying to do is have the audio automatically output to whatever screen the app is open on. ie: If YouTube is playing on the actual iMac screen, the sound would be coming from the iMac internal speakers. Conversely, if I move the Safari window playing YouTube to the Sony TV, the audio would start to play from the TV instead.

Is this possible either natively or via third party app control?