Topic: More Extensive MapCollisions() ?

Hello. I've always noticed that in Mappy, it has 4 collision boxes. I've asked Robin about this and he said that it was for testing collisions in different sectors of a block (for instance, Only testing between 32x16 if the top two boxes are checked on a 32x32 block). This is particularly interesting to me because i am making a small RPG and there are certain tiles in the set that are edge tiles or tiles that only have an "object" like a wall in only half the block, and with the collisions checking the entire 32x32 area, can be rather restrictive and ugly ingame. Does anyone know how to check for these parameters, and if Pub.Mappy already has this built into it?