Sub navigation on rollover problem

Hi flash experts. i am creating a flash navigation and on rollover, i have created a sub menu. now, the problem is, is that since the main nav links are buttons, when the curser rolls over the area of the sub menu (without rolling over the proper main link) the whole nav is displayed (main nav link WITH the sub menu).

ok, if you understood my problem there, all i would like is… when on rolling over the sub menu area, nothing to appear - only appear when rolling over the proper main link.

a perfect example of what i am referring to is the top navigation bar at www.macromedia.com

if anybody could help, that would be great. thanks.