Change the Screen Saver "Start After" options in Mountain Lion
If you're using Open Directory and OS X Server, you can push manifests to the client machines using Workgroup Manager (MCX). This, of course, depends on what version of OS X Server you are using. My familiarity is with Lion Server, but documentation exists for MCX and Directory Services in other OS X Server versions.

While I am not sure you can eliminate the options for screensaver timing, you can force the client machine into a specific value using the plist and MCX.

Helpful Links:


How to Manage Settings Using the Preference Editor
This link is for Leopard, but it is relevant to how OS X Server and MCX handle screensaver settings.