Hello!
My suggestion involves using GPOs and OUs in AD.
1) On a Domain Controller, Create two OUs (Organization Units), one for StudentComputers and the other for TeacherComputers.
2) Move the lab PCs into the StudentComputers OU and the 30 other PCs into the TeacherComputers OU.
3) Now, right-click the TeacherComputers OU and select Properties...then the Group Policy tab.
4) Next you'll create a new Group Policy will be linked to this OU. Do this by navigating down the new GP to COMPUTER CONFIGURATION\WINDOWS SETTINGS\SECURITY SETTINGS\LOCAL POLICIES\USER RIGHTS ASSIGNMENT.
5) Double-click the entry for LOG ON LOCALLY. This will open a new window for configuration.
6) Make sure to remove only the USERS group from this setting.Add the individual groups who should have access to the PCs (e.g. teachers, admins, etc.).
If these steps are followed, it will work as requested.
Cheers!
~Sean