Overlapping transitions within a .swf


I have a .swf with 5 sections. I am able to transition between sections where each section has an outro and intro. So at the moment when you are in a section and you click the button for another section, it plays the outro and then the intro of the new section. East enough when there is no overlapping. Now I was hoping to transition the backgrounds so that when you click a section, the outro plays, then the new section’s background begins to appear on top of the old background (it is revealed using an animated mask), then the new section intros. This would make the transition more seamless.

Any ideas?