I have the same setup and wondered the same thing.
There are a mess of splitters behind the wall in the basement. One of these days I plan to map it out.
Would be nice if they included a schematic.
2016 RAM 3500 DRW 4x4 LB LoneStar Edition, w/Timbrens, Andersen Ultimate 2, Swift Hitch SH04 WiFi Backup/Rear View Camera
2018 Chaparral 360IBL w/Tireminder SMART TPMS, Furrion Wireless Observation System, Progressive EMS-HW50C
2006 RAM 3500 DRW LoneStar Edition
2011 Starcraft 392BHU w/Andersen No-Sway hitch