There’s not a DGG symbol for the wheel motion, so you can’t bind for that explicitly; but the suppressMouse idea should work, though I think you want to set suppressMouse = False, meaning to allow the wheel_up and wheel_down events (as well as all other mouse button events) to be seen even though the mouse is over the frame.
If a frame isn’t clickable, Panda doesn’t create a frame for it, and so doesn’t track whether the mouse is over it or not. If you want this behavior, you have to make it clickable by passing state = DGG.NORMAL.
David