Trying to get an 'expanding' menu slider effect

1

Please view the attached SWF to know what I mean, but I want to create a box-shaped slider that slides to each menu button when the mouse is over it. I know how to create a slider, but since each menu button is a different word (length), I want the box to expand/shrink to nicely surround whichever button is mouse is over. Can anyone help? Thanks in advance…