How can I originate emails to recipients NOT listed in email headers (e.g. like how SMTP works)?

Question

My add-in does "forensic mailing" (all email recipients receive imperceptibly different steganographic mail body content) for the purpose of identifying policy infractions (e.g. "leaks"). e.g. This means that when an email is sent:-

From: Person A
To: person B 
Cc: person C
Bcc: person D

that 4 different individual emails are generated (the original in the senders "Sent" folder, plus a new version for each of the 3 recipients = 4 total).

Using SMTP, it's a simple matter to set the appropriate headers, and use "RCPT TO" 3 times (in 3 different sessions) to send each mail.

What would be the equivalent or any other available way to originate my emails using "Microsoft Techniques" ? Is it possible to perform "SMTP over EWS" or similar, so I can re-use my existing (Linux) codebase ?

e.g. Is there some way to specify a "Bcc" recipient, along with the "To:" and "Cc:" email headers, and then transmit the mail to that Bcc recipient only, to emulate SMTP ?

Answer 1

Looks like the only way is to use SMTP:-
https://learn.microsoft.com/en-gb/exchange/client-developer/legacy-protocols/how-to-authenticate-an-imap-pop-smtp-application-by-using-oauth
with authoirty from:
https://learn.microsoft.com/en-us/office/dev/add-ins/develop/sso-in-office-add-ins#example-access-token