Sure, it's possible, but I strongly recommend against it. Users find such non-intuitive features extremely disagreeable.

If you want to pursue it, research "JavaScript scrolltop" to point you in the right direction.

The issue is this: when thousands of users visit hundreds of thousands of pages, and the vast majority handle navigation a certain way, then, right or wrong, that becomes the expected way. It's called "User Expecatation" or "The User Model". Then, when your site violates that expectation, it creates irritation and annoyance: an unpleasant experience.

The only way to break through this is if your site COMPLETELY breaks the User Model - nothing is as expected, and the user is forced to "start over" and explore the new model. Some good examples are Flash sites: http://www.nike.com/nikeskateboarding/v2/main.html

So unless you want a completely avant-garde site, avoid scrolling menus!