Looking for an app that manages sound sources on the Mac

I don't know if this exists. But it should.

When I use and iPhone or an iPad, if I click a video, activate a song, or get a phone call, the device knows to mute the sound if it was coming from another source, and turn your attention to the newly initiated music source and pick it back up.

This is great. Problem is my mac can't do this.

I want to know if there is software that does this.