Play track at volume feature for sonos?

I’m trying to get my sonos to play a web stream at volume 20. I set up a test switch and got the web stream url, but if I have it on another station, it just turns that station back on instead of the station I told it to. Any ideas?

I had a setup working with something like this to hear TV when walking to kitchen for a drink, but had to abandon due to low WAF during cooking. My most consistent results came from setting up my stream (I was casting from my HTPC using “Stream what you hear”) as a favorited station in Sonos. After smartthings picked it up as having been played, it worked reasonably well. Best of luck with this!