Preloading several SWFs in order in the main movie

what is the simplest way to preload several SWFs into the main movie, one after another? The objective is to make the next swf to load just after the previous one has been fully loaded, reducing the wait of the preloadings.

Another important details is that the others swfs have to be “invisible” for the user, until he clicks on the “load” button, that will actually show the swfs and hide the previous one.