[ACL] File containing users authorized to forward their emails ?

[Frank Bonnet]

Hello

Would it be possible with Postfix to have a file containing users 
authorized to
use the .forward facility ?
We really need such utility , students are playing too much with forwarding
and this generate a lot of troubles with great free email providers, but 
in the
same time our professors and other employees really need it so we really
want to separate "Normal users" from students for that utility.

We use UNIX system with standard users ( not virtual )

thank you for any advice.