Rear entertainment system volume

[Rubenjp]

I'm having an issue that hopefully someone can help me out on. I have an 08 Tahoe with the rear entertainment system dvd and the radio behind the center console. So my issue is how can I get the dvd to play audio to the WIRED headphones without having to change the front radio to the FM channel. Basically the headphones work on 88.5 but I have to put the front radio on that station, meaning the whole speaker system can hear the dvd playing. Is there a way how the front radio can play any station or CD without having to change the station to 88.5 for the rear system? Any help would be greatly appreciated.