The talkgroups show up on the zones that the radios are affiliated to. Most of the time you'll find them staying on their respective zones (east groups on east zone, etc.), but not always. All it takes is one portable in a hall to drag comms over from another zone. The Sunrise Propane comms (TPS and TFS) were up on all four zones.
Then it isn't like Toronto EMS, where all of the talkgroups are on the south tower, but they'll also be on different towers depending on where the paramedic is? IE, a southeast car goes to the northwest end of the city.... SE would then appear on the west zone.