Internet Bandwidth

Is it really possible to have a dedicated bandwidth within a 512Kb Frame Relay for use by the Admin staff only? We are a University campus located in Fiji, using an FIR (512Kb) link to the server in Rockhampton, Australia. We have about 900 students – 144 student computers. Whenever the students are on the internet, the student administration aren’t able to log onto their database in Rockhampton which they need to do throughout the day to update or retrieve information.

Instead of restricting the students at certain times of the day – so that the admin staff can do their work, I was wondering if there was a possibility of having just a dedicated amount of bandwidth set aside for them.