That was not helpful at all, because you cut and pasted irrelevant information that didn't even remotely answer the question I asked. I wasn't asking how to set up a stereo pair.
Here is the question again.
Once I have set up a stereo pair, I would like play music to that pair as part of a routine. Can I set the output for the routine to be the stereo pair instead of just an individual speaker. I'm asking if stereo pairs appear as speaker options in routines, like here:
I do Not have a stereo pair so I'm making some assumtion
1st set up and Name your pair follow these instruction below
Please note that paired speakers only support music content. We do not reccomend line-out and Bluetooth connections to external speakers.
To create a speaker set proceed this way:
1. Place your devices in the same room, several ft (1 m) apart from each other.
Note: If you’re using Echo Sub, place it on the floor in the same room as the other speakers.
2. In the Alexa app, select the "Devices" icon, and then the + icon.
3. Select "Add Stereo Pair / Subwoofer."
4. Select "Speaker Sets," and then follow the on-screen instructions.
I have to assume that because you have named the pair that name will show up in the play from settings in Routines Alexa App . Routines > + > When this happens > your choice > Add Action > music > make your selection > From > name of pair
Hopefully some one who has done this has a definitive answer