How to secure Samba for an NT network

I have an NT network using Domain logons to control access. I would like to configure a Linux pc to provide directories for users and map the drives on the workstations as users log in. I want to be able to control access to the linux directories based on the NT domain login account, preventing users from accessing any directories other than their own. Also, I want to be able to assign a group directory and control which users can access the group directory for shared projects or all membersof a department. Anyone have any experience with this or any ideas of how it can be accomplished?