If you mean can different groups of users have different permissions to the share and all of its' contents, the answer is yes. You can map many different kinds of users to a shared folder and allow some to "read & execute", some to "modify" some "full control" or you can go into the NTFS Advanced settings and set very granular permissions. These are set by right clicking on the file or directory -> Properties -> Security. Always grant access by security group membership, not to individual users.
The most common method to restrict access to shared folders is to set the "Share Permissions" to "Everyone - Full" and restrict access with the NTFS Permission Set, i.e. if a user is logged on they have access to the share, but will only be able to open it if they're listed on the NTFS Access Control List. Using a combination of Share & NTFS Permissions is possible, but only leads to confusion and doesn't offer any better security. If you're a NT System Administrator you should learn NTFS Permissions like the back of your hand, i.e. very well.
This is a pretty exhaustive "how to" on shared folders & NTFS Permissions.
http://www.microsoft.com/technet/tr.../windows2000serv/maintain/operate/adminsf.asp
Patrick Rouse
Microsoft MVP - Terminal Server
www.workthin.com
