Changing I/O Priorities

Hello,

I have recently learned that Vista has an I/O priority system in place. This
interests me greatly, as I often run several programs that all work with
large files, causing my normal programs (Say, my media player) to hiccup and
have problems.

My question is this: Is it possible to change the I/O priority of an
application -without- having the application specifically written to use the
system? I am interested in writing a utility that would be able to change the
I/O priority of applications in a manner similar to Task Manager being able
to change process priorities.

Is this possible? Any links to information about how to go about this or
more appropriate newsgroups are very much appreciated.