smtp users group for saslauthd?

I'm trying to get sending mail in postfix working with sasl authentication In this article I found the author says to create a group for sasl authentication and then add users one by one to the group That seems like an unwanted pain, I don't see why I would need to do that Below's the line which it's suggested to put in newly created file /etc/pam.d/smtpd How can I rewrite the line to exclude the need for the group file

auth required pam_listfile.so onerr=fail item=group sense=allow file=/etc/postfix/sasl-group.allowed