Hi Rachel. Tell us what version of Exchange you are going to install??? If you move to Exchange 2007 you can use the Delivery Options tab from the mailbox properties of the user
You can automatically forward any incoming messages to another recipient:
Forward to Select this check box to enable message forwarding. If you select this check box, you must then select a recipient.
Click Browse to open the Select Recipient dialog box. This dialog box displays a list of all recipients in your Exchange organization. Click the recipient to whom you want to forward messages, and then click OK. You can also use the Search box to search for a specific recipient.
Select the Deliver message to both forwarding address and mailbox check box to have a copy of the message delivered to the mailbox user as well as to the forwarding address. This check box is available only if the Forward to check box is selected. By default, when a forwarding address is configured, all messages are forwarded to the selected recipient—no messages are delivered to the mailbox user.
Hope this was helpful