Swf transitions -- HELP

hello, need help with swf transitions, would someone be so kind to help? basically i have 20 buttons in my main movie loading 20 different swf(s).
each of external swf has 2 frames (frame labels: ‘in’ and ‘out’ my swf transition consists of sending currently loaded swf to play the frame ‘out’ while loading new swf file playing the ‘in’ frame. works fine, except i have so much code on each button triggering the transitions (loading and unloading on various levels)…getting messy.
i found a tutorial online on swf transitions where all the movies are loaded onto the same level and swf transition was still possible. but, the first swf is loaded right away, while i want loading to be enabled only with buttons…i know it has to do something with variables, but is out of my actionscripting knowledge range. here is the tutorial, by the way, maybe someone can improve the code and make even better file out of it.
http://www.hed.swin.edu.au/design/tutorials/flash/smooth_transitions/index.php
would appreciate any help.
thanx