ActionScript 2.0 :: Playing Loaded Swf For There Full Frames

I'm trying to work out the best practices to determine a loaded swfs (via loadMovie()) total frames, then tell the swf file (parent) that has loaded the mentioned swf (child) to play that swf for its total frames. The reason being is that I want to make sure the loaded swfs (children) are played properly all the way through regardless of lag, processor slow down etc. I've got this working but using a setInterval loop which relys on a millisecond variable in an xml file. I want to replace this with an function that does the above.