Preloading external swf

Hi:
I do know how to make preloaders but I was curious on how to load an external swf.

Do you load them making a preloader for the swf which is being loaded, or from the main movie _root level make a preloader for the external swf.

My question is basically where to make the preloader.

-Only one on the main movie and that loads each individual external swf.
-Or one on each external swf?

I make it in the main movie, why would you repeat the work for every movie you load
unless the design needs it?, and even so I think is better to make just one that can be costumize on runtime just not to do same work more than once.

SHO

Could you expand on this please? I’d quite like to know how to use 1 preloader for all my external content! I guess its using a function ?