MX buttonMC probs

i’m having problems w my MX btnMC functions making multiple hits:

here’s the sich: i’ve got a series of MCs that are being dynamically attached to the stage, and inside each MC is a btnMC that attaches a third MC based on the variable that it is passed.

here’s the code inside the btnMC;

this.onMouseDown = function () {
//_root.loadSubMenuMC(subName);
attachMovie(“Sub_MenuOO”,subMenuOO, 2)
}

what is happening is that if there when i click on one of these MCs, it seems like all of them are being triggered, so my single action click is multiplied by how ever many MCs have the same btnMC inside. i’m still trying to grok my way around MXs new methods, so it’s probably something that i haven’t quite grasped yet–any ideas? thanks in advance…
-mojo