sql - group by clause, aggregate returning first record values for rest of fields.

[Gqcy <gmufasa01@xxxxxxxxx>]

I have a file with 6 fields, I want to aggregate by the first three 
fields (jobname, user, jobnumber), I want to return the "first values 
found" for the rest of the fields in the file.
I can get min() to kinda work, but that is field dependent.


select usrinusr, usrinjob, usrinnbr, usrinlvl, usrinpgm, usrintstmp
from mgpll/usrinpf1
group by usrinusr, usrinjob, usrinnbr
order by usrinnbr

I want to return the values in the first record returned for the group 
record by usrinusr, usrinjob, usrinnbr...