Hide names and addresses in a personal distribution list
To keep the names and e-mail addresses of people included on a personal distribution list private, or hidden, use the Bcc field.
Note It's not possible to display the distribution list name in the To box, without allowing it to be expanded to show the entire list of names and e-mail addresses. This procedure suggests using the sender's name in the To box.
In an open message, add your e-mail address in the To box.
In the Bcc box, add the distribution list.
Type your message and click Send.
I dont see the Bcc box.
In an open message, on the Message Options tab, in the Fields group, click Show Bcc.