Multiple menus in one?

Hi, i am building a extremely large website, my issue is that when im doing say regions and countries the menu is massive specially as its structured like

World
-Region
--Country

length isn’t the issue in design sense, its that the menu is soo big that when i go to edit it, its so long and full WordPress takes an age to load it, is there really no way to make multiple menus and add the menus to the single primary menu area?(top of the page)

surely this would cut down on load issues and so on?