Unable to schedule process to insert Unrestricted Life Event for Retro Termination

I faced an issue in end dating the Unrestricted enrollments by inserting Unrestricted life event after termination for which we have created a custom lookup type - 'BEN_BENEFIT_RELATION_STATUS with lookup code-ACTIVE_AFTER_TERMINATION. After which we were able to insert Unrestricted LE after Termination. but it is a manual process. Our requirement is to End date the Unrestricted coverages by inserting it through scheduled process. and here the terminations are back dated. So how can we insert Unrestricted Life event on the termination date through schedule process to end date the enrollments.