code:

\newenvironment{dblpmatrix}{\left(\begin{matrix}}{\end{matrix}\right)}
\def\dblpmatrixvert{\end{matrix}\right.\left|\,\,\begin{matrix}}


bsp:

\[
	\begin{dblpmatrix}
		1&2&3&4\\
		1b&2&3&4\\
		1&2b&3&4bb\\
	\dblpmatrixvert
		1&2\\
		a16&a4\\
		1&2\\
	\end{dblpmatrix}
\]