18. Mai 2016 um 00:17
On Tue, 17 May 2016 23:09:16 +0200

In case Wolfgang's answer was not clear: use "extreme" tables
(\startxtable) rather than "natural" tables (\bTABLE). This mechanism
uses 'framed' and is more flexible.
There is no need to switch from natural to extreme tables because both
tables uses framed for the cells. What is necessary to create individual
borders for a cell is either a metapost background where you can solid,
dashed etc. lines or custom frame types which can be defined with
the \install(left|right|top|bottom)framerenderer command.