Thanks to you both. This solves a longstanding annoyance with Podcast Addict in particular, and my Subaru Bluetooth audio system: Every time I start the car, Bluetooth connects automatically, and Podcast Addict begins to play the last podcast I listened to. No setting in the app or car could solve this problem.
With your assistance, I now have a flow set up which waits for the Subaru to connect to BT, and then issues a stop command to the P.A. player. Big smile.