I think this works in 6.0...i don't have 6 on my current machine, but I seem to recall it in 5.5...I may be mistaken.
By privilege Set Group:
If ( Get(PriviliegeSetName) = "user")
Go to Layout 1
ElseIf ( Get(PriviliegeSetName) = "superuser")
Go to Layout 2
ElseIf ( Get(PriviliegeSetName) = "superduperuser")
Go to Layout 3
Go to Layout 4
Same thing could work using accountnames using the Get(AccountName) function.
Note: avoid using Get(Username) since it is user modifiable thus not secure.
Thanks to you, I've also noticed that there's a slew of conditions and functions I knew nothing about! This is gonna be great!