For this, you can use a pair of RCA "y" adapters to split the 2 RCA outs into four. If you only connect one RCA to the amp it would lose approx 3-6dB as oppose to having 2 connected.
A "y" adapter looks like -------->
RCA Y adapter.jpg. You can get probably find these at futureshop or the source and they are very cheap. Hope this helps...