Thanks for sharing, @Alex_Burrows!
@James posted details on a similar approach using virtual devices to aggregate status using the Rule Engine in the following post:
I would also note that with the newest beta features, you could use a true/false variable in place of the virtual devices - making this a bit easier to setup.
We also just added a new feature to the Variable tiles (in beta) this evening that enables you to change the action of the tile to Hyperlink. I believe this will help you achieve the full vision of what you are looking to do as you can choose to either make the ‘container’ tiles run a Rule which toggles the lights in the ‘container’ on/off accordingly (using the new $.runRule("RULEID") syntax)… or even just use it as a normal hyperlink to navigate to another dashboard showing all the lights in the ‘container’.