Can I add Navigation to a 2003 honda accord without Navigation?

I have a 2003 Honda accord EX coupe without Navigation but it has a 6 disc CD changer I was looking to buy a factory unit with navigation my only problem is all of the navi units I see do not have a 6 disc CD changer. I have been looking on ebay...so does this mean I lose my 6 disc and just have 1? Would I be able to use 6 CD'S but just without the 6 ons? Does anyone have any ideas?