2007 Prius radio plus bluetooth

I recently purchased a 2007 Prius package 6 with JBL. The 'bluetooth' is only for phone calls, not for apps (music, navigation, etc.) on a smartphone. If you have the radio on and you use the Prius nav, the nav 'sounds' will be played while the radio is playing. However, if you use the 'aux' function to have music or navigation come from your phone through the speakers of the car, it 'stops' the radio to give you the 'nav directions.' Is there any way to 'combine' the use of 'aux' phone functions (like a nav app.) at the same time as the car radio is playing?