Thank you, Wolfgang. Wolfgang Schuster wrote:
Here is this example used in natural table:
\starttext \setupTABLE[frame=off] \bTABLE[align={middle,lohi}] \bTR \bTD A \eTD \bTD AA \eTD \bTD[nr=5]$\left.\blackrule[width=0pt,height=14mm]\right\}$\eTD \bTD[nr=5] description \eTD \eTR \bTR\bTD B \eTD\bTD BB \eTD\eTR \bTR\bTD C \eTD\bTD CC \eTD\eTR \bTR\bTD D \eTD\bTD DD \eTD\eTR \bTR\bTD E \eTD\bTD EE \eTD\eTR \eTABLE \stoptext
you can misuse the mathmode.
Hope not. This is only the part of the story -- minimal example. Delimiter should be the part of more complex table.
\starttext
\startformula \startmatrix[left=\left.,right=\right\},style=\rm] \NC A \NC AA \NR \NC B \NC BB \NR \NC C \NC CC \NR \NC D \NC DD \NR \NC E \NC EE \NR \stopmatrix \text{ description} \stopformula
\stoptext