You can use the built-in Matter engine to do intersection detection.
Concerning your file I am not the author of it… so if you want to stick to the approach, consider this a friendly hint for an alternative, much like the example from @h_classen
Currently, drag & drop is still a very code involved thing in Hype. Maybe a good next topic for the Hype Power Pack as @h_classen already suggested. We will see…