use the following DFSORT/ICETOOL JCL which will give you desired results
//STEP0100 EXEC PGM=ICETOOL
//TOOLMSG DD SYSOUT=*
//DFSMSG DD SYSOUT=*
//IN DD *
AAAAAA 123456
AAAAAA 234567
AAAAAA 456789
BBBBBB 111111
BBBBBB 222222
----+----1----+----2----+----3----+----4----+----5----+----6--
CCCCCC 333333
//OUT DD SYSOUT=*
//TOOLIN DD *
SPLICE FROM(IN) TO(OUT) ON(1,6,CH) WITH(15,7) WITH(22,7) -
WITHANY KEEPNODUPS USING(CTL1)
//CTL1CNTL DD *
SORT FIELDS=COPY
INREC IFOUTLEN=80,IFTHEN=(WHEN=INIT,BUILD=(1,6,81:8,6)),
IFTHEN=(WHEN=GROUP,KEYBEGIN=(1,6),PUSH=(87:SEQ=1)),
IFTHEN=(WHEN=(87,1,ZD,EQ,1),OVERLAY=(08:81,6)),
IFTHEN=(WHEN=(87,1,ZD,EQ,2),OVERLAY=(15:81,6)),
IFTHEN=(WHEN=(87,1,ZD,EQ,3),OVERLAY=(22:81,6))
//*