Actionscript

So Im make this interactive thing…
It has a preloader and after its done it will transition to the main screen.
When im done the whole project, main will have subsections and those subsections will go back to main. I only want that transition from the preloader to main, not subsection to main. And i dont want two frames for main with preloader transition and one for no transition. What is a possiblity for me?