The formatting of this string must comply with » RFC 2822. Some examples are: email@example.com firstname.lastname@example.org, email@example.com User <firstname.lastname@example.org> User <email@example.com>, Another User <firstname.lastname@example.org>
On my email app, I have the email config file emailconf.php in another directory. I enter all that information then make the call for it in the main email.php file. Yes it is separated by commas, not semi's but I think also spaces worked the last time I had an app doing this for me too but can't confirm.