Need to make Android SatNav send messages as Phone not A2DP

[AC Question]

I have a car radio with BT. When a call arrives on my Android phone, the call will interrupt the radio, and when the call ends the radio will continue.

I also have a SatNav (CoPilot) on my phone. When that has something to say it does so on the A2DP channel, so it gets lost. It will be heard only if the radio is playing BT input and not radio input. Is there a way to make Android send these messages as 'Phone' instead of 'A2DP' so they will interrupt the radio like a phone call? OK, the application should do this, but it doesn't, perhaps I can get Android to do it for me.