The FIFO option only seems to work when reading in (therefore concatenating) the entire GDG family.

Has anybody figured out a JCL-only way to read generation (0) in FIFO order? This would be especially useful for interfaces where you want to DISP=(OLD,DELETE,KEEP) the (0) generation, i.e. delete it after successfully processing it; thereby giving the first-in file the highest priority in getting processed in a job where you only want to pull in one generation at a time.