adding indash cd to MS Limited?

has anyone successfully added another in dash cd player to a montero sport limited while still keeping the cd changer reciever? I have seen pictures somewhere that people have added one on the bottom deck on the dash, but a guy a best buy told me if i did that, the factory cdchanger/radio/cassette/reciever deck would not work since there was only one set of connections. can anyone testify against this?

I just bought a 2003 Montero Sport LS and it has both players installed:
1- AM/FM with CD on top slot (2nd slot has a door).
2- A 6 CD Changer at the bottom & being controlled by Unit #1.

Both players work well, but I don't know how they wire them.