OnMetaData and Duration

Is there any way to add parameters to onMetaData?

I have a variable in a movieclip that needs to hold the duration but I can’t figure out how to make it so the function see’s the movieclip.

Here’s the idea:

function runVideo():void 
    var totalLength:unit;
    theMovieClip.totalLength = 0;

function theMeta(data:Object):void
    theMovieClip.totalLength = data.duration;

So basically, how can I make it so theMovieClip.totalLength equals data.duration. I can’t have it be a global variable because there will be multiple of movieclips/videos using this function and variable.

Any help would be greatly appreciated!