%
\defineregister[learnedshort][compress=yes]
\setupregister[learnedshort][style=sansbold, textstyle=slanted, n=2, pagenumber=yes, indicator=no]
%
\defineregister[learnedlong][compress=yes]
\setupregister[learnedlong][style=sansbold, textstyle=slanted, n=2, pagenumber=yes, indicator=no]
%
\define[1]\learnedis{%
    \txt{} \getvalue{#1}
    \learnedshort{#1}
    \learnedlong{#1}
}
\define[1]\learned{%
    \learnedshort{#1}
    \learnedlong{\getvalue{#1}}
}

\starttext

\learnedis{blah blah}

\input knuth

\learnedis{some more}


    \startchapter[title=Standards]
        \placelearnedshort
    \stopchapter
    
\stoptext

My question is, can I have references to the Workbook page numbers in the textbook? And visa-versa?

For instance, the Textbook index currently looks like this:

-------------

Standards

blah blah 1

some more 2

--------------

With the data in the Workbook it might look like this: