If you have the AMI port in the glove box, try the Bovee Tune2Air AMI or similar. This is expensive but worth the money according to others. I use a cheaper one which does have the odd hiccup and doesn't support the media controls. 8 ball pool
Search for "bluetooth a2dp ami" or similar to see other alternatives. AMI is the port in the glove box, A2DP is the bluetooth streamning standard.
Also your device (phone or whatever you use) will need to support at least 2 bluetooth connections simultaniously (most modern smartphones do).
Music streaming
in Audi A4 (B8) Forum
Posted
Thank you I will give it a look