Disable menu links?

I’ve setup my main menu to have 6 top level pages, with a handful of sub-pages under each (that become visible upon hover). Each of the top level menu items is a link to a new page. Is there any way to disable this, so clicking the top level menu item does NOT take the user to a new page?

e.g. I’d like a top level menu item named ‘Pages.’ When you mouse over the ‘Pages’ menu item, a list of pages (‘Page 1,’ ‘Page 2,’ Page 3,’ etc) drops down, but if you click on ‘Pages,’ nothing happens.