If you're not familiar with DFSORT and DFSORT's ICETOOL, I'd suggest reading through "z/OS DFSORT: Getting Started". It's an excellent tutorial, with lots of examples, that will show you how to use DFSORT, DFSORT's ICETOOL and DFSORT Symbols. You can access it online, along with all of the other DFSORT books, from:
I have downloaded the manuals. They are proving helpful with some other stuff I have to do. No "code changes" (except JCL) allowed at this stage of the project for some bizzare reason but I think you can do almost anything with these sorts. Very powerful software.