How can I use multiple copies of a blueprint actor to mask the ground near them?

[L.F.A]

@MaxLevelNPC

I finally started to see why I probably wasn’t going to get it to work with the MPC,

ClockWorkOcean is correct, MPC will not work as expected because each gem needs to react to the player overlaps independently from one to another.
Here is an overview of the suggested solution:

The same logic applies to the emissive parameter (Set Scalar Parameter Value).