Targeting mc's between two movies loaded into holders

I have myself a base swf with two empty holders. Each holder loads a different movie into the base.swf.

On click of the button in either of the loaded movies I’d like to turn off the other movies mc. Normally I would understand how to do this, but I can’t figure out the pathing due to the fact I’m loading into the holders.

I’ve attached an example if anyone has a second to have a look.

Thanks for your time, Jason.