\useregister[workbookA][03_workbook][learnedlong][WB~1:~]
\useregister[workbookB][04_workbook][learnedlong][WB~2:~]
\useregister[workbookC][05_workbook][learnedlong][WB~3:~]
\useregister[workbookD][06_workbook][learnedlong][WB~4:~]




        \startchapter[title=Standards]                        \placeregister[learnedlong,workbookA,workbookB,workbookC,workbookD]
        \stopchapter

I setup a custon index that lists items from four different workbooks. 

The problem is in the indexi, it displays entreis like this:
WHST.1.1: 11, 231, WB 1: 124, WB 1: 133, WB 2: 325, WB 2: 345, etc.
In other words, it says WB 1 in front of every page number from the first workbook.
Is there any way to consolidate the page numbers by book, e.g. output instead like this:
WHST.1.1: 11, 231, WB1: 124, 133, WB 2: 325, 345
In other words, it list all page numbers for Workbook 1 right after WB 1: instead of placing WB 1 in front of every single page from Workbook 1?
--Joel