Enabling Next Button after using hotspots to trigger layers

Hi guys! I'm working on a project where I have made hotspots trigger other layers. I have disabled the Next button when the timeline starts, and want the user to click on each hotspot before they can move on. I can't figure out how to make this happen with hotspots. I figured out how to do it with buttons, but I can't figure out how to do it with hotspots because they don't have states.

HELP! Thanks!