Network Printing on Roaming Profiles

We have a Windows Server 2003 and XP workstation domain. All users have
roaming profiles. I need to set permissions so users can not add printers
and that specific printers are only available to specific machines and not
to users as they move from location to location.

I have installed the appropriate printers on the workstations as local
printers but this means that each machine has it's own print queue so we
can't manage them. I tried adding the computer accounts to the printer
permissions on the print server but anyone in any location can print to any
printer!

I have read and searched just about everywhere for a solution but to no
avail - please help!

Thanks