Adjusting volume on Sonos grouped speakers

Still just getting started with Sonos, and the only real issue that I’m having is with adjusting the volume with webCoRE. I have two rooms grouped, but due to size, they need to be set at different volume levels. I want to set or fade the volume to certain levels at different times of the day, but whenever I set the primary speaker, the grouped speaker automatically gets set to the same volume level. Is this a bug with the Sonos stuff or am I setting something wrong?

*Added the wait to try and give a pause between, but doesn’t seem to have an effect.