Email, Messaging, & Video Calls Email Sending an Email to Undisclosed Recipients in Mozilla Protect the privacy of your email contacts By Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated August 09, 2019 Wikimedia Commons Email Yahoo! Mail Gmail Tweet Share Email All the people you know are connected by no more than one degree of separation—their connection to you. Chances are they do not all know each other directly, though. You and they might prefer for you not to share all their email addresses when you mail people as a group. It is possible to email the group while keeping all the recipients' names and addresses private in Mozilla Thunderbird. The process isn't complicated; it just requires a little advance effort to create an address book entry for Undisclosed Recipients. Create an Address Book Entry for Undisclosed Recipients To make mailing undisclosed recipients easier, set up a special address book entry in Thunderbird for that purpose: Select Tools > Address Book or Window > Address Book from the menu in Mozilla Thunderbird.Click New Contact.Type Undisclosed in the field next to First.Type Recipients in the field next to Last.Type your own email address in the field next to Email.Click OK. Send an Email to Undisclosed Recipients in Thunderbird To compose and send a message to undisclosed recipients in Mozilla Thunderbird: Begin with a new message.Click Contacts in the message's toolbar.Highlight Undisclosed Recipients.Click Add to To:.Highlight all other desired recipients in the Contacts pane.Drag and drop them to the second address field.Click on that second address field To:.Select Bcc: from the drop-down menu.Add additional recipients that aren't in your address book to the Bcc: field. Separate them from the existing contacts and from each other with commas. You can also use Mozilla Thunderbird address book groups to add multiple recipients in one go.Compose your message and send it. The recipients will see Undisclosed Recipients in the area where they normally see other recipients' names and email addresses thus preserving the privacy of all involved.