How to change reply_to multiple email address in Vtiger 6.4 for all the outgoing mails via Mail Manager?

Question

I want to use multiple email address like if I want email1 and email2 fields together in the replyto is it possible in Vtiger

Thank you

I tried

$email1 = $currentUserModel->get('email1'); $email2 = $currentUserModel->get('email2'); $replyTo = $email2 . ',' . $email1;

this is what I tried but did not work Do you have any other solution