Nested SubMenus

On my site, I am having a problem with nested submenus. Example: Main Menu Item -> Sub Menu Item 1 -->Sub Menu Item 1A --->Sub Menu Item1AA When I mouse over Sub Menu Item 1, both Sub Menu Item 1A and Sub Menu Item 1AA are fully expanded. I only want sub menu item 1AA to expand when I mouse over 1A. Hopefully this makes sense.