[NTG-context] meta-FLOWcharts or ... ?

Hi all, I would try to design a figure like http://www.nibua-r.org/ConTeXt/sample.png FLOWcharts seems to be a good tool to do that, but I have some troubles to get "Simulation" and "Colision Detection" frames... First, I thought of a meta-flowchart but I'm not sure that's possible. Any idea ? TIA Renaud