using custom depth in material to and return boolean if material overlaps

Hi all,

In my road editor i’d like to allow the build of a road B if it doesn’t overlap another road among RoadsArray.

While i’m previewing RoadB, id like to use custom depth in its material to set every pixel in overlapping area to black.

How to do so please, and is there a native blueprint function, that says : If one of my material pixels is black, then return true ?