Can you make modular swfs talk to each other?

Can you control the timelines, scale, rotation, dynamic content etc of separate modular swfs which are connected through /embedded within another swf? or are their actions sealed away, deaf from each other? For example if I made a menu a separate swf from the content it wants to control- would this not work?
And if it does work, I assume it takes _root -based actions to do so? I hope I make sense, my flash lingo can be sloppy sometimes

I know I went through this in a “intermediate flash” class I just took, but I’ve already forgotten. this doesn’t seem like an easy topic to search. If it does work then that’s very exciting!!