How can I make cascade mesh particles collide with terrain objects?

Hello, sorry if this has been posted or is in the wrong category, but I’ve scoured google and the closest answer I could find was an invalid YouTube link…

Anyway, I’ve created a number of mesh particle systems that have the actor collision module attached, and they are all colliding beautifully with the objects that I want them to (static environment objects, enemy characters) and not colliding with the things I don’t want them to (the player character, projectiles). The only thing that I want them to collide with that I can’t for the life of me get them to is a landscape object. The particles spawn as promised, fall with gravity, and pass right through my landscape. I would like them to collide with it and freeze translation until they disappear as they do with static environment meshes. Any help here would be greatly appreciated. I’ll attach a picture of the particle’s Actor Collision settings, as well as the terrain object’s collision settings as they are now.