Automatically amending privilege sets

Have a database with several test for students enclosed. When I want students to do a test I manually change their privilege set to allow access to 4 or 5 layouts. After the test I do the reverse. Sometimes, I forget a layour. Ideally I want to create a field for each test with a yes/no flag which will make the appropriate layouts automatically available to the students. When the test is done, just change the flag. I would imaging a script but have no idea where to go from there.