Sorry I misunderstood your original question. I tried it out yesterday and was able to have my S2 3g paired with my car and with my Galaxy s6 Edge at the same time.
In order to do this I had to first have the S2 in Standalone mode so it would pair with the car. Then when I turned the bluetooth on my phone back on it connected to the phone as well. As expected, my car would not connect to my phone as it already recognized the S2 as a "phone" that it was connected to and my car will not connect to two phones at the same time.