help me help me

hai i am working in private company , in my company we have 20 client and 1 server.
win2003 server and all client are win xp, i have one doubt , in my office have three section that's accounts, designing and office section,i want restrict particular user enter into any one of client system that allow only particular application. example : office section user enter system 3 that user only use ms-office,excel they not open other application ,next day the same user enter in system 5 that also work only the same application other application must not open .every user have user id and password how to restrict this type help me my buddies.