Adding a Symbol inside another Symbol

Hey is it possible to add a Symbol inside another Symbol?

Googling has yielded… not much, and stabbing at in the in the dark with

LargeSymbol.addChild(InsideSymbol);

Doesn’t not work. With an error 1061: Call to possible undefined method addChild through a reference with static type Class.

Is this really simple? Or not possible in AS3?

Any help is appreciated Thanks in Advance.