By default, the 323 will share everything to everyone; if you look at the default network access list, it will look something like:
Volume_1 / Volume_1 / ALL / <blank comment> / yes / yes / RW
Volume_2 / Volume_2 / ALL / <blank comment> / yes / yes / RW
What you need to do is create the appropriate user accounts in users/groups first. Then you can delete the default network access list and start over. You're going to need to create a "user" folder in your backup (Volume_2) if you want the same kind of persmissions work like you have it on Volume_1. What you want could look like:
Volume_1 / Volume_1 / edifonzo / admin share / yes / yes / RW
User1 / Volume_1/Users/User1 / user1's share / yes / yes / RW
User2 / Volume_1/Users/User2 / user2's share / yes / yes / RW
Volume_2 / Volume_2 / edifonzo / admin backup share / yes / yes / RW
Backup_User1 / Volume_2/Users/Backup_User1 / user1's backup share / yes / yes / RW
Backup_User2 / Volume_2/Users/Backup_User2 / user2's backup share / yes / yes / RW
The reason for the user folder in the backup drive as well is if you want a given user to be restricted to a specific location while you have access to everything, you're going to have to do it in a way that works with the 323 since you can't have multiple permissions on a folder like you can on Windows Server System.
Hope this helps you out.