[NTG-context] Drawing vertical and horizontal lines inside a matrix

Hello, Can I draw vertical and horizontal lines inside a matrix? I get ugly result by underlining and "sidelining" the elements, but what I neeed is to underline the whole row and draw a line next to the whole column. \startformula T = \left[ {\matrix{ a & b & {c |} & p \cr d & e & {f |} & q \cr {\underline h } & {\underline i } & {\underline j |} & r \cr l & m & {n |} & s \cr } } \right].\stopformula The attached picture shows how it looks now. Vyatcheslav