You can do it using the TRIG - to control it..
That means you have to Schedule it - as many times as you need it to run..
SCHID = 010, 1200, 14:00
triggering is based of SCHID on TRIGID SCHID=010 - TRIG=012
SCHID=010 - TRIG-014 But remember JES won't allow the same job name to execute at the same time - due suggest the scheduling via an interval period. Understanding the time will change based of the last runs end time. perhaps so maybe if you shorten your interval down to 30 minutes...