If you are referring to the new Lighting Groups feature added to the new Samsung SmartThings mobile app in early June, SmartThings has not exposed an API for it yet. For that matter, Lighting Groups can’t even be used in other SmartThings features like rules or scenes yet!
We’ve had some discussion with the SmartThings engineering teams and it’s on their list to expose control of lighting groups via scenes, rules, and ultimately via API calls as well. That being said, it sounds like there is a platform gap for subscribing to lighting group events for status updates - it’s just not possible at all today.
Basically, they’ve only exposed Lighting Groups for manual control via the mobile app. There are plans to add support for automating control of the lighting groups, but the ability to properly track events/state of lighting groups doesn’t have a clear roadmap plan from SmartThings.
In the meantime, the recommended approach would be to use a Virtual Switch for controlling the lights. You could then create a Smart Lighting automation to turn Patio 1 and Patio 2 on/off whenever the virtual switch is turned on/off.
Note: As long as both of your patio lights can run local, since virtual switches and Smart Lighting both run local on SmartThings, the virtual switch could then be used in any other local automations.