Restrict Color for Some Installs

Hi,

We have a new HP LaserJet 500 color M551.  It's networked, naturally.  We have no domain, and instead have a workgroup.  We are a public library and I would like to restrict this machine from printing in color on some patron computers.

I just want to disable color printing for some installs, then, of course, prevent users from changing this setting in printer preferences.

Thoughts?

Thanks!

Manny