How to make a particular window respond to a mouse scroll message?

Suppose I have two windows, Form1 and Form2. I want Form1 to respond to mouse scroll message so I call Form1.SetFocus first. But the mouse srcoll message is still responded by Form2. It looks like Form2 always catches the mouse scroll messgae. How can I make Form1 to receive the mouse scroll message? Thanks for your inputs.

Not exactly sure, but I would try to write a global mouse hook similar to keyboard.