"Additional Rules" in Software restriction policy

Hi all,

Is there a way I can add "Hash Rules" to my "Additional Rules/Software
Restriction Policy without having to use the MMC?

What I'd envisage is a program (or script) that trawls from a start point
through every sub-directory (user home drives in this case) looking for .EXE
files that they shouldn't have, calculating the hash, and adding it to the
rules list.

I could see this being run daily or weekly to keep the hash rules current.
Of course, there would also have to be a way to detect duplicate entries,
and not add them.

Mark