The apparent answer for this is seemingly 'No' but I am wondering if there is a way or trick.

I have multiple bitmap buttons of non-square shape. Because of their odd shape I can overlap them and they will still look good on screen, which is what I want - that certain layout.

The problem is that because underlying button in reality is square (which I am subclassing), the bitmap of one button may overlay with the non-bitmap area of the other button (in the underlying square). This means that 2nd bitmap button will not receive notification because the press is registered with top level window only.

Is there a way that both windows can receive the notification and check if they are in the hot spot, they will respond? I know this is against windows design and rather look silly to ask but I am wondering if there is some kind of way.