Spotify Connect link TO companion app

[caseymorris61]

When I want to play Spotify on my Sonos speakers from my Spotify iOS app, in the device picker, my Sonos speakers have an "options" menu, i.e. the 3 dots that open a menu. This menu provides a UI with a button to "Group Rooms", and clicking on this button opens the Sonos app on my iOS device. This is a feature I would be interested in replicating with my own speaker project with my own companion app. Is it a feature available to all partners that implement the eSDK? If so, can someone point me to the reference in the API that enables this? Reading the API, I have not been able to figure out how to add this functionality.