Adding a slider to a Navigations bar

Hi.

Im wondering how i would go about adding a slider to a navigation bar.
I tried using the “mouse follow with easing” and just limiting it to one axis then adding the buttons under my the follow.
What i REALLY need to find out is how to get the slider or follow to stop at each button.
An example:www.disasterlabs.com

Do you add a certain code to the button on the “over” frame? Or is the slider totally seperate?

If anyone knows how i could go about doing this, please help

Thanks alot!