speaker wiring ?

[cb suburban]

I installed a new Kenwood CD player using a Metra dash kit and wiring adapter plug.  I wired the plug exactly like the package said.  It had wire color code for the front and rear speakers.  My Suburban has 6 speakers stock, front doors, rear doors, and rear cargo area(headliner).  The front doors work, along with the rear headliner speakers, but no rear dors.  Does any one know where to hook up to get the rear doors to work. I was wondering about maybe running the rear door and headliner speaker for each side in series, at least that way they would all work.  Any suggestion would be great.