[HELP] using bounds to make head bob?

Working on my first RPGish game, and I'm wanting to give the person the ability to pick a class and the head for the class. So these are two independent movie clips. I was curious is their a way to get the bounds of my body so that I can make the head always at the top of the body, so that w2hen the sholders go up and down the head does accodingly also, or would it be better and easier to process it if I animated it by hand?

example http://abuseadam.com/theTale/tale.html

pick the female to see the head, the male is an example of without a head...

ive never tried an RPG or isometric, but it seems to me it would be easiest to just make a MC called character_mc, then within that have body_mc and head_mc. then you can move the character around and the head stays at relatively the same place. but by saying "head bobbing" it sounds like maybe you just mean as the animation of the shoulders lowers a little or moves, the head moves with it? definately do that by hand

yeah I was figuring doing it by hand was the solution. Just requires more work ^_^;

just to let you now it is resolved. I upload a small demo of picking a head for the one female type. I used hand animation after fiddling with making a key point, which I had to animate by hand anyway so decided to just make the heads bob by hand. Now ... adding all the other char types and heads ... male and female. oh yeah ... you can look at stuff with the ctrl button ... all that you can look at on the current demo map is trees ... but ... hey you can look at them!