Get all subconcepts of a concept in baselanguage (java).

Hi,

I have a concept called"A" and several concepts (sub-concepts?) called"B", "C", and "D" that extend concept "A".  Knowing concept "A" is there anyway to get a list of all concepts that extends from "A"?

I could hard-code the sub-concepts into the generator but it would make the code more brittle. It's far less likely the super-concept would change.