Pete on "Display a specific level of a category tree"

I'm trying to find a way to display a specific category level of a post.

For example. I have a post with a hierarchical category tree structure like below...

Parent cat
Child cat A
Child cat B
Child cat C

I'm looking for a nifty piece code I can use within the loop that will allow me to display any of the category levels, not all the levels.

Clear as mud? :)

Thanks heaps - Pete