Been playing around with this for a bit and found the following:
body_shape_entered(body_rid: RID, body: Node, body_shape_index: int, local_shape_index: int). The docs are saying
body_shape_index the index of the Shape2D of the PhysicsBody2D or TileMap used by the Physics2DServer. Get the CollisionShape2D node with
This sounds exactly like what I'm trying to do, but when calling this i get an error: Nonexistent function shapeownerget_owner in base TileMap. Any ideas on what I'm doing wrong?