Control external swf from main timeline

I have a external SWF loading into a target on my main swf. Is there a way to control the timeline from the loaded movie from the main timeline. So , control B timeline from A. I’ve tried mcholder.gotoAndPlay (2); but it won’t work. Also, how can I get the mumbers of frames from the external swf into the main timeline. Will a global variable work?

Thanks