ActionScript 3.0 :: Passing Vars In MovieClip Heirarchy?

I have a bunch of nested movieclips. I set a var "foo" on the topmost clip. A child clip wants to know the value of foo: easy enough, i just call parent.foo.But what if I don't know how far down the tree the child resides in? Worse, what if foo changes every so often on new branches?My first thought was to simply add thisvar foo = parent.footo every clip, but this of course requires every clip have that line, or it breaks, and it doens'tus if a new child is inserted, or if a parent "foo" value changes.I was thinking that I could call a recursive function, where a child asks it parent, then its parent's parent, etc, for the value of foo along its particular branch...

function whatIsFoo(obj) {
if(obj.parent.foo==undefined) {
return whatIsFoo(obj.parent)

[code]......