Trigger a Relay from Inside Cam App

I use V3 Cams on Android to watch gates and doors in multiple applications. When I see someone at the door or gate that I want to let in, I go to another app like ewelink to trigger a sonoff/shelly to open the door or gate via a relay. OK work around for me but not anyone else in my family.

Idea, while in the cam view, I can turn on the spot or flood light attached to the camera. How can I use that light button to trigger a relay? What is the best way/hack to get this done?