Passing mouse event through an object?

I have isometric tiles that are put together to form a map. Because the graphics are isometric, and the images themselves are rectangles (with transparent corners) I was wondering if there’s way to pass a mouse event through image being clicked if it’s being clicked at a point that is transparent onto the object that is layered below it. Using the bitmapData class I already know how to check if the position being clicked is transparent or not, just not the second part.