If I'm understanding the question correctly.
When opening the "Home" app, tap the + in the top left corner and select "Create speaker group". Then choose which speakers you want to add to the group 2 speakers in question to said group, and choose a name.
That way when you request music to be played - it will automatically play on both speakers.
Hope this helps.
willie-breedt, thanks for the insights!
Tom22, checking back in if the provided steps and information above helps? You might want to check this guide for additional information about creating and managing speaker groups. Let us know if you have other questions or concerns.