Want to run Sky and Sky+ cables off two coax cables

minibob

Hi, Recently moved into a new house, which has two coax wires coming down from the attic to a centralised box underneath the stairs. My intention is to centrally locate a Sky+ and Sky box and take feeds from these boxes back into an amplifier, which feeds the in-home coax wiring system. I was recently informed that there should be three coaxes coming down from the attic (One for the normal Sky box and two required for Sky+). So there is one cable and it is not possible to reopen walls etc... to fis the additional cables down from the attic.
Thus, is there anyone that knows how to utilise the two cables, in-order to feed a Sky+ and Sky box? There is power in the attic, and it sounds like there might need to be active components added to either end to resolve the issue. If so part numbers etcc. of the required components would be extremely useful.
Thanks,

Tony

As I mentioned in my email to you a stacker de-stacker is required for this. Hopefully the existing cables are of good enough quality for this to work as the unit uses very high freqs.