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 Only from, and then click
Add.
In the Select Recipient dialog box, select the
recipients whose e-mail the mail-enabled recipient can receive, and
then click Add. Repeat this step for each recipient.