ActionScript 2.0 :: Preload External Swfs In Mc?

i'm trying to preload 5 external swfs into an MC outside the stage area, one right after the other, and when one is finished loading into that clip, the next one replaces that one and starts loading in that same MC. that way they will all already have been preloaded once they are needed by the user. the main thing is that once a swf is finished loading, it needs to be removed and the new one take it's place and start loading. (i've noticed that having multiple external swfs on the stage at the same time slows down the main movie.)

currently, each external swf has a preloader and some code that tells it to check if the movie has been preloaded or not. if it's already preloaded, it skips the preloader and goes right to the start of the movie. if it hasn't been preloaded, it goes through the preloader sequence. my hope is that by preloading all the swfs before off the stage, when they are needed no preloaders will have to be shown, the swfs would just start.

right now the way i'm doing it is that on the five nav buttons, i have on release code that tells it to load the needed external swf (external1.swf) on the viewable stage on maincontainer_mc, and to load the next one (external2.swf) on outsidecontainer_mc, which is off the stage. then when the user clicks the next button, that one has on release code that tells it to load external2.swf on maincontainer_mc (which was preloaded earlier) and to simultaneously load external3.swf on the unseen MC.

this works great, but while the user is reading the content on the first swf, other swfs could be getting preloaded in the background instead of just one at a time how i'm doing it now.

does anyone know of a way to load a swf and unload it when it's finished loading, and then load the next one in line, etc. on the same mc?