I tried the below syncsort jcl assuming the record length of 80 and VB record format for all the input files. The merge works fine.
//STEP001 EXEC PGM=SORT
//SYSOUT DD SYSOUT=*
//SORTIN DD DSN=VBFILE1,DISP=SHR
// DD DSN=VBFILE3,DISP=SHR
// DD DSN=VBFILE2,DISP=SHR
// DD DSN=VBFILE4,DISP=SHR
//SORTOUT DD DSN=VBFILE5,DISP=(,CATLG,DELETE),
// SPACE=(TRK,(3,1),RLSE),RECFM=VB,LRECL=320,DSORG=PS
//SYSIN DD *
SORT FIELDS=(92,1,CH,A)
SUM FIELDS=(32,8,40,8,48,2,51,8,59,8,67,2,70,8,78,4),FORMAT=BI
INREC IFTHEN=(WHEN=INIT,OVERLAY=(32:18Z,
51:18Z,70:12Z,90:SEQNUM,2,ZD,92:C'A')),
IFTHEN=(WHEN=(90,2,ZD,EQ,2),OVERLAY=(32:5,18)),
IFTHEN=(WHEN=(90,2,ZD,EQ,3),OVERLAY=(51:5,18)),
IFTHEN=(WHEN=(90,2,ZD,EQ,4),OVERLAY=(70:5,12))
OUTREC BUILD=(1,31,32,51,SQZ=(SHIFT=LEFT,MID=C','))
Output is
TRL,V05,00,201409,20140831,000000000446967,000000000002788,000071355053