Emails with multiple addresses

I just sent my question but I’m not certain that I did it correctly-

Are there processes, plug-ins or software that permits sending an email to multiple addresses without exposing the addresses by listing them in the “To:” line of the email header?

My PC has fully updated MS Office, Outlook, Outlook Express, Windows and XP2. I’ve unsuccessfully searched your how-to and download files.

Many thanks for your prompt and professional response, Abe