Car audio help needed(rca plugs)

[SAWYER]

I replaced my factory unit that hooked up to a factory amp. I had to buy a special wiring harness that had rca cables, two red/white sets. The back of my deck(Pioneer 3000IB) has two sets of rca output. Only my factory sub and either my front speakers or my rear speakers will work depending on which set of rca plugs I have going in to the stereo on a certain side. What are my options to get all my speakers working?

 

[lsd]

I would image the cheapest option would be to get a couple of RCA Y adapters for one of the channels.
http://www.amazon.com/RCA-AH25...or-Cable/dp/B00005T3G9