Exchange 2003 on Windows Server 2003 R2, Client machine - Outlook 2003.

I would like to setup/configure an exchange account that has limited email
capability - to restrict the account user the ability to send internal emails
only. I tried to browse through the settings from Active Directory but could
only find the settings to restrict incoming emails but not outgoing. Could
anyone assist? Many thanks in advance.

kind Regards,

William