Does anyone know if there is an extra channel available in the factory setup to add a camera? I have the four factory cameras, just not sure if there is an extra channel. I'd like to add a camera to my dogs crate, in the backseat, so I'm not having to turn around and try to peer in. Preferred would be the ability to view through the stock system, though if there is a BT option that I can view through AndriodAuto, I could do that as well.