Create Button to "Link" Lights

[rossko57]

This thread explores a similar requirement

Is it possible to create a group switch?

I would like to create a group switch that is something like 'Upstairs Lights", but still be able to toggle the individual. So for example, I could have: Upstairs Hallway Lights: On Master Bedroom Light: Off But if I toggle the ‘Upstairs Lights’ switch they will both turn off or on. In other words, I don’t want the individual switches to change the state of the ‘grouped’ switch. Is this possible? If so, how? Thanks!! I’m getting myhead wrapped around this thing, so if you point me in th…