Yes, it is possible - at least in a limited way. Here's what Pure says about it on their homepage: "Our latest Highway adapters can also be connected to your existing audio system via a simple aux-in cable or via an unused FM frequency. ..."
Now, however, with the still high density of FM stations in Switzerland and many frequencies in use just a few kilometres away, it is no real pleasure to reconfigure the FM transmitter in the Pure if necessary and switch the FM (VHF) radio. You also have to consider whether you want to be able to receive the telephone call of the person you are talking to in the vicinity of the car without being secured.

No, unfortunately not.