Block USB Acess for particular cleint User in Network??Read full

Dear friends,

I want to block USB Access to particular who if login on any machine will not be able to write/copy any thing on pendrive means will have only READ Access not Write/Copy access

We have server 2K3 and Client OS is XP ?

if client was loging on logged in singl comuter then i know to change registry entry but for this need help as it to done on User secrity control Pls Help