The Unified Messaging in BCM50 R3 allows proper emailing of the messages to the users (rather than just the Callpilot Desktop Messaging Client, which just collects the messages from a mailbox on the BCM).
You could try something like this:
1. Set up a mailbox but don't assign it to a phone (or assign to an unused phone). It'll be used just for faxing.
2. Set up Express Messaging on that mailbox, so that the fax line DDI points to the mailbox.
3. To set up the Message Forwarding, log into the Mailbox-Manager for the fax mailbox.
In there, enable Message Forwarding and put in the email address to which you want the faxes sent.
It may not be possible to enter more than one email address in there.
What you could do is set up a mailing list (either with your ISP, or on your mail server, etc) so that one email address is aliases to many.
4. In Callpilot Manager, in Configuration, System-Properties, enter the SMTP mail server address. This is the server to which the BCM will sent the emails. It could be your interneal exchange server or your ISP's mail server, etc.
This sort of setup requires only one UM licence for the fax mailbox. It won't require a UM seat for each receipient.
There's could be more to it, including making sure that the BCM can route mail to the internet, making sure that ISP can send back read-receipts if applicable (including possibly setting up DNS records), but this overview may be just what you're wanting.