Is it possible to show or hide rows of a table by setting a global boolean variable?
\documentclass{minimal}
% some boolean variable X
\begin{document}
\begin{tabular}{ccc}
A & B & C \\
A & B & C \\
A & B & C \\ %show this row iff X is true
A & B & C \\
A & B & C \\ % show this row iff X is true
\end{tabular}
\end{document}