A Main Menu activates two Submenues

[Martin]

For a special reason, we would like to have this funny feature:

If a user clicks on a main menu entry, two submenues (or two others menues) should popup.

That means, like "show-menu" could have two entries for a sub menu.

At the end, we would like an submenu like this:

mainmenu1
submenuentry1 submenuentry2 submenuentry3
submenuentry4 submenuentry4 submenuentry5

Any Ideas?