The problem is, your D-Tivo will NOT work on stacked LNB signals! (the other receivers do, because they evidently have "wideband" tuners, which the D-Tivo does NOT - most non-DVR receivers made in the past couple yearts DO wideband, although you have to enable it through the menu)
You are going to get a couple of destackers & a wideband splitter - you would split the incoming signal, then run each side of the splitter to a stacker, which then goes to each sat input of your D-Tivo.