Switch Bluetooth device

[ptestfall]

Hello,
what I am trying to accomplish is to automatically switch between between two bluetooth devices.
The first one is a headset that should be connected all the time except when I enter my car. The second is the hands-free-phone device of my car that should automatically connect once in range of my phone.
Interestingly half of the time the phone does switch from my headset to the car device and back automatically. But half of the time it does not. That is why I try to make it happen with Automagic.
So far I have failed to make that happen with Automagic. I am not really experienced and hope that someone more experienced with a better understanding of Automagic could give me some help.

From the general Idea I thought to periodically look for a specific bluetooth device and when found to connect to it and when its not found to connect to the other bluetooth device.
But I dont understand hot to do that with Automagic and bluetooth. With WLAN it was easy to create.

optional:
Once I start my car the second bluetooth device starts to automatically connect to the phone. Instead of periodically checking for a specific bluetooth device, could Automagic not somehow use the connection attempt as a trigger?

Thanks for any help,
pt