Control dynamic content from main timeline

I’m sure this has been asked many times before…but I can’t find anything that will help so I’m gonna ask again…sorry to all of you that have seen this question a million times before…

can you control/access the timeline of a dynamically loaded swf? If so how?

if I use this code:

loadMovie("a.swf", "contentLoader");

how can I access the timeline of “a.swf” from the main timeline of my flash movie? is it possible?

thanks in advance!