GJOB statement
Purpose: All jobs in a job group must be defined with an appropriate GJOB or SJOB statement.
A GJOB is followed by as many dependencies (BEFORE, AFTER, CONCURRENT) as required for the job. All jobs referenced by the dependencies must be defined within the JOBGROUP. You cannot have dependencies on jobs outside of the JOBGROUP (or in another JOBGROUP). A job can be defined before or after the dependencies that reference the job.
References: For information about the JES initialization parameters that provide installation defaults, see z/OS JES2 Initialization and Tuning Reference.