I don't know a good way to do that with the menus. Looks like you have 9 pages all at the root level and you just want to group them, but there is no grouping within a level.
However, if you think of it a menu is just a list of links. You can easily create a list of links styled or grouped any way you like using an Html Content feature. The menus are a convenience of the content management system because when you create a page it shows up magically in the menu, but you could uncheck the "Include In Menu" option in page settings and then just make your own menu as you like, it just won't be updated automatically when you add new pages, instead you will have to edit your custom menu.
Hope it helps,