The topic pretty much concisely describes the objective functionality.
This specifically mitigates using Cc: and Bcc: fields for 2nd and subsequent recipients who are otherwise at parity with one another, and prevents leaking e-mail addresses among the >1 recipients, and reduces the iterative finding and 'edit message as new' slog to just a different, single delivery-mode click.
... and doesn't effectively lower the priority of any message with the 'undisclosed-recipients' address.
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The mail merge addon offers what you seek as well as numerous other personalisation options.