Any way to reference specific collision meshes?

I’ve got a box and I want to do a few things with it.

I want the box to be destroyed if it’s hit with a projectile, and I want the box to kill the player ONLY if the player collides with the bottom of the box (gets squashed.)

At current, the box properly registers the projectile collision and dies if shot anywhere, but the player collision is detected all over the box.

I found out how to add additional collision meshes in the static mesh editor, but I’m wondering how I can reference each one.

And if I’m just an idiot, how I could go about doing this differently. I’ve spent all day googling, I just don’t really know what I’m googling for, I guess.

Any one able to help me out?