dual lnb -> multiplexor -> splitting signal?

[wzl]

i have a dual lnb setup on the roof w/ a multiplexor.. 3 lines come into the house... 1 used upstairs.. 1spare upstairs... 1 running through the walls, ceilings, and walls again to reach downstairs for a nice, neat installation.... i just got a d-tivo for downstairs and want to use both sat inputs.. is there any way to use the single line downstairs... i dont want to have to go through the hassles of bringing in an addition line from upstairs?

[BubbleLamp]

The only way to do that is with a stacker/destacker arrangement. They aren't cheap, 9th tee sells them.