A really fun grid to play, well done.
(Although I could be pedantic and point out that Northern doesn’t officially fit into its group)

Solved the grid with a minute to go, accidentally sorting Australian territories and states, by pressing randomly to find the ones which weren't in the time zone group. The Australian states group was the only group I failed to identify once they were sorted (my not spotting it was nothing to do with Northern being a territory rather than a state).