It looks like you're trying to invent the wheel again, try using kixtart, it's includen in the nt4 resource kit, if you don't have it you can also download it from www.kixtart.org.
It has anything you need, and is simpler in use than vb scripting.Some sample rules:
If ingroup( "Friends" )
use x: "\\mainserver\c$"
endif
If @userid = "Ron"
use y: "\\mainserver\alldata$"
endif
If ingroup( "nitwits" )=0 or @userid = "BigBoss
Logout
endif
Etc.
For win98 and Win96 users, you must have the kixtart RPC running on the ntserver, since they cannot check user or group entrys.
This one is easy, just put the kixtart files in your netlogon, type kxrpc -install, go to the services and start the service.
But thisis all explained better in the manual provided.
I'm sure you like the utility, since you can change registry setting, and everything else, according to group membership, or username.
Happy scripting ;)
Ron.