One thing your professor could do would be make Send= Editor  and then
define Editor as a neutral party, a cooperative colleague perhaps.
The Editor just makes sure all information about the original sender
is removed.  Shouldn't be too difficult, nor time consuming since it
would only be for the class evaluation period.  Might want to have
a different Editor for each list so there is no confusion as to what
goes to which list.  Or the Editor could be one student from each class:
A from class A Edits the list for class B, B from class B edits C, C
edits A.
 
Or, your could just have his students send their comments to some third
party to start with, to be sent on, names/addresses removed.
 
        Douglas Winship    Austin, Texas    [log in to unmask]
                    Secondary AUTOCAT Listowner