rear radio controls for 2011, LTZ

I’m sure this has already been addressed but I have a 2011, Silverado 3500HD LTZ and would like to have the rear radio controls just as my previous had. After reading several posts on this issue I’ve found that because of the USB input the older rear controls won’t hook up. What do I need to install the rear radio controls? My truck currently has the navigation radio with the Bose speaker system. Rear controls is an option with the entertainment package however I didn’t want the overhead DVD player and didn’t realize the newer LTZ models didn’t include this standard. Any help would be much appreciated.