Does anybody know if you can add headrest screens to the factory Nav/DVD? I have the overhead monitor, just wanted to add a couple more screens if possible. I don't know if there are any A/V jacks on the factory system or if it runs off of data cables or what not. Even if there is only one set of A/V jacks and they are used to run the factory overhead, I'm okay with that, I'll just run splitters. Just need to know if this is possible or not. Otherwise I may have to throw my Pioneer D3 in, but I really don't want to. Thanks.