We will try to help you to solve the issue.
You can sent mail to those people as BCC
No one can see the mail ids present in the BCC field.
And if you are creating a group name with all those mail ids only the group name will be displayed. But as the receiver is part of the group, there is a chance that he/she can find out all the members of the group.
Let me know which mail service are you using.
I am using G-mail. That was a good solution because the list is only 33 people. So rather that use the group, I added the names in the group directly from my address book, without any reference to a group. That should preserve everyone's provacy, right?