Send e-mail to undisclosed recipients

QUESTION:
Recipient A allow to see all other recipients but Recipient A himself must be hidden from all other recipients
Where to put Recipient A ?
ANSWER:
...
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When composing new message, leave "To:" section blank and put all destination e-mails in "Bcc:" section

Blind carbon copy
To send a message to multiple parties with none of them knowing the other recipients. This can be accomplished by addressing a message to oneself and filling in the actual intended recipients in the BCC field

Bcc vs. Cc
Example of CC vs BCC
From: Frank Sinatra
To: Kurt Cobain
Cc: Bob Dylan; Jim Morrison
Bcc: Mark Knopfler; Paul McCartney

In the above example, all recipients of the email (including Mark Knopfler and Paul McCartney) will see the following email header information when they receive the email:

From: Frank Sinatra
To: Kurt Cobain
Cc: Bob Dylan; Jim Morrison
This means that none of the recipients will know who the Bcc recipients are. Each of the BCCed recipients will, of course, realize that they were on BCC but they will not know who else was on BCC.
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