[actionscript 2] drawing API help with attachMovie

I hope I can articulate this well. I’ve been searching forums and the internet for a few days trying to find a way to do the following but with no luck.

I’m creating a mind mapping application and so far I have an interface in which the user can click on a button and a new concept will appear. The button attaches a new copy of a movieclip to the stage. What I want to do now is add a button onto the attached movieclip (its called rectangleDraw in my source) that will draw a line to another instance of the attached movie clip. So essentially the user will click the two movieclips to be linked and a line will be drawn between the two.
I can’t seem to figure out a logical way to do this. I am familiar with the drawing API and I’m sure that I can set some variables to do this.

I’d be very grateful if you could help me with the logic behind this concept or even look at my source: