You didn't answer about the order of the output data. Is it OK sorted on the Key?
If 41-80 on both of the records which make a pair are blank, then there would be room for the data to live on one record (but no room for exansion on an 80-byte lrecl PDS). You can have a PDS with LRECL 160, or whatever you like.
Unsurprisingly, Kolusu's code is going to work how he intended, not how you think. Even if not at work, the manuals are available on the Web and you could check on GROUP and PUSH and anything else you are not sure of. Kolusu is about 20,000 times better at this than I, so he doesn't need my support on this