VIRTUAL - User Permissions and Ownership

I am trying to set up the "Postfix Virtual Doamin Hosting" - 2nd example
in the HOWTO - and have run into a bit of snag.

I created:
/var/mail/vhosts/1stdomain.com/username1
/var/mail/vhosts/2nddomain.com/anotherusername

but I have the error "Permissions denied"

"who" should the owner be of :/var/mail/vhosts/1stdomain.com/username1"
(it is currently root)
What "GROUP" should it be
(I manually changed to to "users")
What file permissions
(I have manually used chmod for 664)

The reason for the 2nd example is so that I do NOT have to declare the
users on the local (SuSE Linux) box.