Is there a way to have signals from the AUX input play simultaneously with the mp3 play? I have a scanner hooked up to the AUX and I thought that it would be cool to hear what comes over the scanner while I was listening to music during the scanner dead time. Could it be made for the music to cut out when there is a signal on AUX or for them to both play at the same time with my music in the background of the scanner output?