Is there a way to limit access to certain records based on the logged in user?

Example: I have a grade database with 2 sections of a course. How can I give 1 TA access to one of the sections and a second TA access to the other section, without having to worry about 1 TA changing the other's grades?

We have a network db on document control to allow users to log in to and change their own records only. This is done by creating a field in the db containing a local password for each person - in addition to the normal db log-in password.

The layout containing the passwords is limited to high level FM log-in password holders.

When the local password matches the name of the person logging in, a script is run which finds the data relating to that person only.