You can prevent mail-enabled recipients from receiving e-mail by
specifying that the mail-enabled recipient can receive e-mail from
everyone except recipients you specify.
To specify who the mail-enabled recipient cannot receive e-mail
from:
On the Start menu, point to
Programs, point to Administrative Tools, and then
click Active Directory Users and Computers.
In the console tree, expand the Windows 2000 domain.
Double-click Users, or double-click the node that contains
the recipient information you want to modify.
In the details pane, double-click the mail-enabled recipient
you are modifying.
On the Exchange General tab, under Message
restrictions, select From everyone except, and then
click Add.
In the Select Recipient dialog box, select the
recipients that you do not want the mail-enabled recipient to
receive e-mail from, and then click Add. Repeat this step
for each recipient.