Do I have control on external loaded files?

Ok say I have a big comeplete Flash website.

The website is composed of:
-The main stage
-Movie Clip that loads external swfs 1 (let’s call this “A”)
-Movie Clip that loads external swfs 2 (let’s call this “Z”)

So say A is a movie clip that loads a menu (external swf). Can I control Z (like changing frames and so on), by clicking buttons on A (since it’s a menu)?

I hope I was clear.

So it is possible, how would the paths be written?