How to disable Bluetooth auto connect for only a specific device (car)

My wife and I drive the same car and use the bluetooth connectivity while driving without issue. However, for example, when I pull into the driveway and my wife is talking to someone on the phone her call goes to the car. Same thing happens if the other is on the phone and I leave. The call gets picked up in the garage by the car. I would think there would be a way to disable bluetooth auto connect to the car (only) without impacting all the other bluetooth devices?