Is it possible to define a cell that spans all columns without knowing beforehand how many columns there are? Specifically I would like to do something like this:

\starttext

\bTABLE

  \bTR \bTD[nc=<all>] I span all the columns \eTD \eTR

  \bTR \bTD col 1 \eTD \bTD col 2 \eTD <...> \bTD col n \eTD \eTR

\eTABLE

\stoptext

Is there any expression for <all> that yields the total number of columns? I tried to use \tablecellcolumns but it is undefined if used at this location.

Thank you for any feedback!

Christoph Reller