How to end process tree?

I'm looking for something like "End process tree" form task manager.
I start an application using ShellExecuteEx. I have its handle and TerminateProcess works just fine, however aplication starts its own processes which remain. Sending WM_QUIT message doesn't work at all. Question is how can I kill whole process tree?
I don't care about proper shutwown, so even "brute force" metods will do fine.

thanks for any help

on win2000/XP look into the JOB object, on 95/98/ME hijack create process API to track creation of the child processes

Works like a charm.
Thanks a lot.