Your description of what you want to do is extremely unclear!
I really have no idea what you're trying to do so all I can do is throw out a few guesses.
If you want help, you need to explain clearly what you want to do.
You used "SPLIT" as your Subject, but I don't see anything about splitting files in your description.
You mention two existing files and an output file, but you haven't made it clear what you want to do with those files.
Do you want to create DD statements from the records in an input data set that has their dsnames and attributes?
Do you just want to concatenate/copy XXX.NAME and XXX.NAME1 to XXX.NAME?
Please explain clearly and in detail what you want to do.