Addressing nested clips with dynamic name?

I’m not sure this is a proper title, but please take a look at my problem. :blush:
Let’s say I have a movie clip named MC in stage. The following statements work.

[COLOR=“Olive”]var clipName = “MC”;
this[clipName].y = 100;
[/COLOR]

However, if I put a child movie clip (named childMC) inside that MC movie clip, I’m not able to address the child movie clip by the same fashion. I’ll get an error.

[COLOR=“Olive”]var clipName = “MC.childMC”;
this[clipName].y = 100;
[/COLOR]

Is there any way to address the child movie clip with dynamic name? Thanks for the help!