[NTG-context] Shapes spanning multiple grid cells in flowchart

Hello, I've just started to use Context because of its great flowcharting module. However, I'd like to use shapes that span multiple grid cells. This is what I would like to accomplish: |-------| |-------| |-------| | |<-->| box 2 |<-->| box 3 | | | |-------| |-------| | box 1 | | | |-------| |-------| | |<-->| box 4 |<-->| box 5 | | | |-------| |-------| | | | | | | |-------| I could not find a way to do this in the manual. Every shape in the manual has the same size. Thanks for the help! Martijn