On our directory we have an allowed broadcaster's attribute: so I can do a

if ($action eq "add"){$ldap -> modify ($dn, add => {allowed_broadcaste
+r => $address_to_be_added}) 
          or die "Ya screwed up again!";
[download]

You should have an attribute that you can add/modify so it will only allow certain people can post. You will then need to modify it on the exchange server.

HTH- if it doesn't please show some code and a little more of a description where you are getting stuck.

"The social dynamics of the net are a direct consequence of the fact that nobody has yet developed a Remote Strangulation Protocol." -- Larry Wall