Using parent and child controls
In the HCL Compass interface, you use controls to display fields in record forms. A parent and child control, when used with a reference or reference list field, lets you link related records. By adding a parent and child control to the record form of a UCM-enabled record type, you can provide the developers on your team with the ability to decompose a parent activity into several child activities.
To have the state of the parent activity changed to Complete when all child activities have been completed, you need to write a hook. See the Help for HCL Compass for an example of such a hook.