Restrict E-Mail Use & Other questions

Hello all,

Configuration:
– Windows 2000 Server SP4
– Exchange 2000 Sp3
– Outlook 2000 Clients

I would like to restrict the e-mail use for some users in my organization.
Users should only receive and send e-mails to a list of e-mail addresses (internal and external) that i allow them.

Another subject,

How can i receive an e-mail in two diferent mail-boxes? Not using a distribution list…

Thanks in advance