Well, I haven't found a way to only play specific announcements, but I finally figured out the correct sequence of door openings and closings and train motion to advance the announcements one stop at a time. Took me long enough. What got me was that Aux 2 / F or R / Aux 2 sequence. I didn't realize you had to press Aux 2 twice to close the doors, and then start the train.
And Pdxtrains, there ARE a few testy announcements about moving into the car, etc. 😊 They are only at certain stations, though.