Set lower priority on a process initiated by Hazel

By way of example, I have an active folder which Hazel monitors, into which I drop movie files eg wmv files
An embedded script runs Handbrake to convert to m4v. However the Handbrake process is very cpu intensive and my Mac naturally slows down to accommodate. Easy enough to run renice +20 on the process manually through Terminal.
This is just an example of lots of rules I have which initiate programs which could hog cpu.
I would like to have a generic rule or checkbox setting, that allows me to blanket specify that whatever Hazel is initiating in a rule or set of rules is run at a lower priority. I can build the 'nice' command into my scripts but this is hard wiring when what I'd really like is to be able to say x rule is always run nice-ly at a lower priority.
Can this be done?
thanks
An embedded script runs Handbrake to convert to m4v. However the Handbrake process is very cpu intensive and my Mac naturally slows down to accommodate. Easy enough to run renice +20 on the process manually through Terminal.
This is just an example of lots of rules I have which initiate programs which could hog cpu.
I would like to have a generic rule or checkbox setting, that allows me to blanket specify that whatever Hazel is initiating in a rule or set of rules is run at a lower priority. I can build the 'nice' command into my scripts but this is hard wiring when what I'd really like is to be able to say x rule is always run nice-ly at a lower priority.
Can this be done?
thanks