Mythtv and others use Schedule Direct (SD) website to setup channel listings ( locals, cable, D*, E* and 4dtv). There are other standalone programs like FreeGuide and TVG also, but all of them will only allow one channel listing selection.
It would be nice if they modified their programs to allow selecting multiple listings, that way we can create a listing for each channel and have them merge into one and displayed in the program.
I asked the developers of SD about being able to create custom listing from at least one sat (i.e. G10R)...currently there isn't a way, but they may look into it in the future. If more people inquire about doing this, maybe they will.....