you can just buy an "ipod" fm transmitter from ebay and plug it into the headphone socket and away you go or a tape adaptor if your old school!
The tft screens usually have composite (phono) and S-Video inputs you should be able to get a lead to fit but like s11eeps says post a photo and we can figure it out. It can and has been done, me and my friend kitted out his camper it has a ps2, xbox, tv tuner, sky box, reversing camera and dvd player all hooked up to his 6 tfts with a switch box with a bit of headscratching anything is possible!!!