That function is in 8.4 as well as 8.5, and likely beyond.
Below is the code we use in the Index Information tab, with type PDF.
COORDINATES=IN
INDEXSTARTBY=1
TRIGGER1=ul(1.26,8.29),lr(2.53,8.45),*,'document break text here'
FIELD1=ul(0.45,9.06),lr(3.93,9.27),0,(TRIGGER=1,BASE=0)
FIELD2=ul(3.68,10.37),lr(7.16,10.60),0,(TRIGGER=1,BASE=0)
FIELD3=ul(0.65,10.18),lr(1.51,10.41),0,(TRIGGER=1,BASE=0)
FIELD4=ul(1.58,10.18),lr(2.94,10.41),0,(TRIGGER=1,BASE=0)
FIELD5=ul(3.00,10.18),lr(4.03,10.41),0,(TRIGGER=1,BASE=0)
FIELD6=ul(0.66,10.37),lr(1.52,10.60),0,(TRIGGER=1,BASE=0)
FIELD7=ul(1.58,10.37),lr(2.86,10.60),0,(TRIGGER=1,BASE=0)
/* - separator - */
INDEX1='CUST_NAME',FIELD1,(TYPE=GROUP) /* NAME */
INDEX2='CUST_ADDR',FIELD2,(TYPE=GROUP) /* ADDRESS */
INDEX3='ACCT_NO',FIELD3,(TYPE=GROUP) /* ACCOUNT NUMBER */
INDEX4='AMT_DUE',FIELD4,(TYPE=GROUP) /* AMOUNT DUE */
INDEX5='BILL_CODE',FIELD5,(TYPE=GROUP) /* BILL CODE */
INDEX6='BILL_DATE',FIELD6,(TYPE=GROUP) /* BILL DATE */
INDEX7='DOC_ID',FIELD7,(TYPE=GROUP)
INDEX8='RPT_NAME',FIELD5,(TYPE=GROUP) /* BILL CODE */
/* - separator - */
/* RESTYPE OPTIONS FOR PDF - ALL, NONE, FONT, IMAGE */
/* or FONT,IMAGE */
RESTYPE=ALL
REMOVERES=YES
BOOKMARKS=NO
/* FONTLIB=C:\WINDOWS\Fonts;C:\WINDOWS\Fonts_New */
/* TEMPDIR=C:\TEMP */
FONTLIB=/usr/lpp/Acrobat3/Fonts
TEMPDIR=C:\arstmp