MX yet another Preloader question, help pls

As usual, I’m trying to load external swfs into an empty movie clip on the main timeline of my interface movie.

I’ve currently got it set up (thanks to help from this forum) with a preloader in each external movie clip.

BUT, It’s been suggested that I instead put one preloader in the interface movie to detect every time new data is loaded into my empty movie clip.

That sounds like a FANTASTIC idea, but I have no idea how to make that work. Have tried a bunch of tutorials (including one from Moock) but can’t seem to make it work. Want to start from scratch.

Does anybody know how to do this? Sure it’s easy, but my brain just isn’t getting it.

Any help would be greatly appreciated.