Multiple form submit in functions.php

Hello there,

I have this form in functions.php which ties in with a couple of functions to send emails to a mailing list:

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Which works fine, however I need to add another submit button and text box so the person using it can selectively send the content to just a single e-mail address rather than the entire mailing list. Just wondering if anyone has any ideas? I’ve come from Drupal and not used WordPress in years so just looking for the best route really.

Cheers
Dan