[NTG-context] How to place a (right) brace in a TABLE?

Hi. (Sorry for unclear question in topic.) I want to put a brace (right or left isn't matter now) in a TABLE (may be another table environment) like in below scheme a11 a12| a13 a21 a22| a23 a31 a32 a33 a41 a42 a43 a51 a52| a53 a61 a62| a63 Here '|' marks place and elements which should be grouped by a brace. Thanks in advance, Vladimir Lomov. P.S. I'm new in context and don't have any idea how to achieve this. I thought about graphics (metapost) to draw a brace or join two cells and draw big brace. And, yes I use mkiv and latest beta (context minimal). -- Show your affection, which will probably meet with pleasant response.