Exchange message receive restrictions

[dgsmith]

Right, need to know the quickest way to add our students group into the message receive restrictions for all students. We need to stop students emailing eachother (but still allow sending/receiving from staff) and the only way I can see of doing it is by changing the permissions to allow receiving emails "from all except <student group>".

We have Exchange 2003 on Windows server 2003. We've looked at banning student<>student emailing before but because our version of Exchange is only 2k3 it didn't make it easy. The only way I can see of doing what I suggested above is going through each user individually and changing this permission - is there a quicker way of doing it (script or global config)?

For reference, the area I am referring to is in this picture - "from everyone except <students>"

[dgsmith]

Noone knows anything about doing this? I'd have thought it be a fairly common procedure!