Loading of external swf after each other. Help Please

I have a few objects (say 3) which to be loaded in turn. All of them must be visible on the stage.
Question is: how can I tell object3 waites for object2 to be fully downloaded and then object 3 starts to be loaded into?
I get problems (SOMETIMES) especially on the server that objet2 and object1 or object3 and object2 comes at the same time.
These objects been loaded into different levels of _root.
in frame 1
loadMovie(“movie1.swf”, “object1”);
and in frame 20
loadMovie(“movie2.swf”, “object2”);

and in frame 40
loadMovie(“movie3.swf”, “object3”);
and so on.