To keep the names and e-mail addresses of people included on a personal distribution list private, or hidden, use the Bcc field.
It's not possible to display the distribution list name in the To box without allowing recipients to expand it and show the entire list of names and e-mail addresses.
The following procedure will use the sender's name/address in the To box and the distribution list will be kept hidden in the Bcc box.
Add the Bcc box to your email if it isn't there already
In an open message, on the Message Options or Options tab, in the Fields or Show Fields group, click Show Bcc or Bcc.
Hide the distribution list in the Bcc 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.