Not all talkgroups are in every tower. All statewide talkgroups are (KHP, KBI, Statewide EM, ICS & Interoperability, etc.), but most local TGs are not. When I worked county fire in Finney County years ago, right when they switched on, I could hit towers around southwest KS for our local fire talkgroups, but once I got past the Great Bend area, the radio began giving me "out of range" tones for those TGs. However, I could pull the KHP and other TGs anywhere I went.
Think of the non-statewide TGs as having "regions" within the state that they're assigned to in terms of towers; the best way to guess is to group them much like KHP is organized in troops: if it's in the Troop B area, chances are it'll hit most towers in Troop B, and likely Troop A due to proximity and population, and maybe a few on the edges of C and F.
There are some exceptions of course: Midwest Life Team, EagleMed, LifeWatch, LifeNet, LifeStar and every other EMS service on the system are statewide, as is the KANG, and a few other agencies/groups that otherwise are regionally oriented.
The point behind this is if all TGs are statewide, you could potentially drag down several trunking controllers simultaneously by one person going across the state, and leaving their radio on their home talkgroup, thereby dragging extra traffic across repeaters that don't normally handle it (which is why they assigned dozens of statewide and regional interoperability talkgroups to use for "long distance" communication).
