Prioritize headphone jack for media (but don't disable the rest!)

I can't seem to figure out how to make this happen. I would like media audio to be automatically routed to the headphone jack if it's plugged in, to Bluetooth A2DP audio if there's nothing in the headphone jack, and to the built-in speaker if neither of the other two are connected.

As it is, I can either Let the App Decide, which always seems to choose A2DP over the headphone jack if both are present, or I can specify headphone jack only, which totally disables the other two.

How do I pull this off?

So you want the Headphone Jack to take priority over Bluetooth A2DP? I would like to allow changing priority in the future.

For now, the quick way is to leave "Media audio" on "Let app decide". You can put a widget on the home screen named "Headset toggle". You can set the toggle to ON to force the headset over the Bluetooth A2DP and OFF to switch to Bluetooth.

Ok, I think this widget will do the trick, though it would be nice to have it fully automated. Actualy, a priority system would be useful for all the various input/output methods (Phone, Media, Notification, etc). It would acommodate the user's preferred device for all combinations of connected devices.

In my case, I want to play music through the car stereo, but take calls via bluetooth, but if the car stereo is not connected, I want the media via A2DP, not the built-in speaker.