2
setToEmails() can take a single string email - or an array of emails.
so
$xoopsMailer->setToEmails( array($email, $email2, $email3) );
Would do what you want it to.
"When you can flatten entire cities at a whim, a tendency towards quiet reflection and seeing-things-from-the-other-fellow's-point-of-view is seldom necessary."
Cusix Software