To achieve a norepeat in a specific itemize block, I need to introduce the norepeat at a higher level. This affects all the children of that itemize. See the example below, please. In the multiple-choice block, I want to avoid repetition, but afterward, I want to restore the default behavior.

\define[1]\BoxedNumber{\inframed[width=3ex]{\convertnumber{n}{#1}}}

\defineconversion [BoxedNumber] [\BoxedNumber]

\starttext

\startitemize[BoxedNumber,fit,repeat][stopper=,distance=\spaceamount]
   \item xxx
   \startitemize[BoxedNumber,fit, norepeat][stopper=,distance=\spaceamount]
     \item multiple choice
 \startitemize[A, columns, two, random, fit][stopper={)},style=bold] %%
 \item choice 1
 \item choice 2
 \item choice 3
 \item choice 4
 \stopitemize

 \item normal question 1
 \startitemize[BoxedNumber, repeat] %%
 \item question 1 \par\thinrules[n=2]
 \item question2 \par\thinrules[n=2]

 \stopitemize


   \stopitemize
\stopitemize

\stoptext