A system including a lock class having a plurality of lock families, with each lock family including a plurality of lock cylinders. Each of the lock families has a control pin location which is different from the control pin location of another of the lock families within the lock class. Each of the lock cylinders generally includes a shell, a plug rotatably mounted in the shell, and a control ring rotatably mounted on the plug at the control pin location of the lock family of which the lock cylinder is a member, and a control pin operable to selectively couple the plug with the control ring. Each lock family may be associated with a control key family. Each control key family may include a plurality of control keys, each of which may have a control bitting configured to urge control pins of the associated lock family to a coupling position.