The following mfsort command takes a line sequential file, sortin.dat and sorts its records on a character field starting at position 11 with a length of 4 bytes. The results are output to the file sortout.dat which will include only records for which the sub-string, starting at position 15 of length 3 bytes, is equal to any three consecutive characters in the string 'J69,L92,J82'.
mfsort sort fields=(11,4,ch,a) use sortin.dat org ls record (f 80) give sortout.dat include cond=(15,3,ss,eq,c'J69,L92,J82')