I have 2 locations. My mother is in PA and my home in NC. I want to setup an automation that flashes a light/siren at my home if my mother presses a button at her home. I cannot see a way to link between locations when creating an automation.
Not sure if there is a smartapp that will do that for you, but you could set up a webCoRE instance in each location and then use a http call from one instance to the other to trigger a device or switch.
Maybe IFTTT can help you bridge…?