External SWF Communication

I was wondering if there was a way to have an externally loaded SWF file have a button that can communicate to the file that it was loaded into.

I have a bunch of buckets that I’m loading in externally that and I would like for each of them to have their own back button that tweens the content in the SWF off stage but also to have a movieclip in the main file tween back on.

I’m really stumped as to how to achieve this.

Any help is GREATLY appreciated.