Bluetooth Prioritization

I have multiple devices Bluetooth devices connected to my iPhone. I recently obtained hearing aids that are connected through my iPhone meaning they can stream my phone calls and music through the hearing device to provide a better hearing opportunity for me. I have also synced my phone with my vehicle, via UConnect. To get better music quality, I often plug my phone into the vehicle, and on some occasions listen to music through the Bluetooth software through the car. After getting my hearing aids, there are times throughout my travels that my phone will randomly sync to my hearing aids instead of just staying in the car. This becomes an issue since we are required to be hands free, hence the Bluetooth application. Is there a way to prioritize Bluetooth devices on an iPhone? Is there a way to prioritize Bluetooth audio devices in the order in which I want them to play, like if I am listening to music on my phone through my vehicle, that it stay there and not switch to my hearing aids? Any help or ideas you can provide would be greatly appreciated.