I think you're asking for trouble. Electrically, connecting 2 receivers in parallel should work ok, but if both pick up out-of-phase signals because of different locations and wire lengths, this will result in scrambled signals. If the eyes are completely isolated from each other, so only one at a time has any possibility of receiving the signal from your remote, then it should work ok.
A better solution, although more expensive, would be to simply get a Next Generation RF extender. You just replace one of the batteries in your remote with the NG transmitter, and put the base near your cable box. Since it's RF, it will work everywhere in your house with no aiming required. It runs about $40.