Destroy All of One One object on collision

Hey, basically i have blocks raining down at random intervals, and when the blocks stack up to a ceratin point, i want them ALL to be destroyed. I also want it so that once it hits the thing destroying them all, the script is enabled. Since it is 2d, if it collides with the thing and destroys it, they will never stack.

There’s probably a bunch of different ways to do this, but I’d probably have a master Empty GameObject that checks for when your block pile reaches a certain height (you could do this with a Collider) then it Broadcasts a message to all the blocks, destroying them.