I thought I was understanding what you said but it looks like I am wrong.
Tile area array is all of the tiles under the platform. There is an array for each edge top, bottom, right, and left. When a platform is initialized I do nothing though when it is spawned I have a process check what it should be and hides all but the starting one. When it hides them it goes through the Tile area array and sets the edges for all tiles all edges to 0. When I unhide which I do for the first platform at the start of the game I set all edges for all tiles in the Tile area array to 1. Then I loop through each of the 4 edges and set the 3 edges for that side to 0 for each tile on the edge. Each platform is 4x4 tiles.