I can't think of any case where JCL uses an IP address; it's quite possible that they are being used in control cards that are being miscalled JCL, as is so often the case. If so, a direct use of such a data set would depend on the program; you could probably write a Rexx scriptette to pick out the wanted IP address and edit the control cards.
"You have sat too long for any good you have been doing lately ... Depart, I say; and let us have done with you. In the name of God, go!" -- what I say to a junior programmer at least once a day