A technique for processing telephone calls from a plurality of telephone sources in a vehicle audio system suitably includes providing a first call using a first one of the telephone sources to a user via the vehicle audio system, notifying the user of a second call received via a second one of the telephone sources while the first call is active, and processing an instruction from the user to either suspend the first call and accept the second call or to continue providing the first call. The technique may be implemented in a vehicle audio system that includes an onboard telephone, and may be adapted to work with wireless or other portable telephones carried by drivers and passengers in the vehicle.