gps and bluetooth through speakers

I have a 1994 Mercedes E320 with TV's in the dash, sun visors, and head rests. As of right now I have a PC in my trunk and the video from my computer runs to the dash TV. The other 4 Tv's Videos come from the Head Unit. I have Made a diagram to show:

Now I want to to have my GPS and Bluetooth to go to tweeters on the dash so I can talk on my phone and and also hear the GPS commands while listening to my music. I put two relays together and split the sound. The Positives from the bluetooth and gps unit go to the relay on the right while the negitives go to the relay on the left. As of now I have a swith the changes from bluetooth to gps. The bluetooth should always be on the the gps when I hit the switch. Does anyone see any problems? I made a diagram: