Disable all menu items from top down

Top level menu has items 1-5 going across. Each has up to 10 selections under each. When it is first initiated, I want to disable items 2, 3, 4 until they make a selection from item 1. It looks like I have to sc_menu_disable(EVERY SINGLE SELECTION). Is there any way to disable a top level (item_2) and have it disable all the subs under it? sc_menu_disable(2) and have it also disable the subitems (21, 22, 23…)?