Thanks for the reply! Unfortunately, pre-comping and regular mattes wont work for my purpose. I am trying to achieve a similar effect to this: In this show that my kids watch, the characters have outlines that only show up when they cross over an object with the same fill color. Example being if a h...

Example scenario: I have 4 boxes. Box 1 is blue, Boxes 2 & 3 are a specific color of red and Box 4 is green. I would like Box 1 (blue) to only be visible when overlapping a red box. If Box 1 overlaps Box 4 (green) nothing happens. My question: Is there a way I can matte a shape so that it is onl...