Playing external .swf's in sequence

I have a main navigation .swf and a series of external .swf’s and I am looking to have the external .swf’s play one after the other by default. Currently, I have them playing only when a user clicks on their associated button in the nav bar.

How can I let the main .swf know when one of the external .swf’s has finished playing so that I can trigger the next .swf to start?

Thanks in advance,
:slight_smile: Fitz