When you PTT on one of these talkgroups, all 70+ repeaters on the network are activated, and everyone listening will hear your call. PNW 1 and PNW 2 are FT (Full Time) on all PNW repeaters.
They are the designated calling talkgroups as they have the widest reach on the PNW network.
 Correct use of PNW 1 and PNW 2 is to make a quick call, establish a QSO and then QSY to a more local talkgroup like a TAC.