There used to be some really cool apps before SmartThings shut down Groovy that easily accomplied this (Trend Setter, Dim with Me, Color Coordinator, etc). I don’t think I’ve seen any single solution come out as the defacto recommended approach by the community for Edge.
From a quick search, here’s a few things I found:
- Use Zigbee Light Multifunction Mc to create lighting groups for Zigbee devices.
- Use the Smart Lighting SmartApp within SmartThings (Labs) for syncing on/off state from a switch if it’s available within your country
- Use SharpTools Rules along with a virtual device or a true/false variable to sync light states
- Here’s an old example by James that could be updated to use some of the new features like Multi Device Triggers, Multi Device Actions, and Multi Device conditions to greatly simplify the rule configuration.
Using SharpTools rules is probably the most flexible. And for your particular use-case, if you primarily just wanted to see if any of the lights within your group was on with the option to click it to see which lights are on, it would be a really good fit.
A rule like the following would trigger when any of the monitored lights change* and then if any of the lights are on, it would set your true/false variable to true… otherwise it would set it to false.
*The generic ‘change’ trigger is available in beta. You could also just use a trigger for when any of the lights change to on and another for when any of the lights change to off for the same effect if you prefer.
Then you could add that Variable to your dashboard and customize it with a light icon and change the background color when it’s “on” (true). And you could configure the click action on the tile to open another dashboard showing all the lights within that area.