parallel and "nicing" on Windows

R-sig-hpc'ers:

We recently ran into an issue on our Windows application server where a
researcher spawned more workers than cores via parallel backend + a foreach
job, and, of course, this made the server more or less unusable to anyone
else while they were running.  We were able to solve this by manually
changing the priority on the spawned processes to low priority, but this
brought up a question -- is there a way to set the spawned processes to low
priority on Windows (or renice them on linux/pc) from within R?  Ideally
this would be when the parallel cluster is launched.  Thoughts?

--j