Creating a Sequence of Groups with Instructors, Rotating to never match groups previously done

[Aufty]

For a professional training session we need to easily create groups:

1. I have a class of 36 students
2. I have 12 group leaders
3. There is always 12 groups of 3 students with 1 group leader.
3. I need 4 sessions with no repeats of students or group leaders.

Can you suggest a formula or method of setting up these groups?

It would be very helpful.
Thank you.