[NTG-context] annotated text: main text in narrower text, annotations on the right

Hello list, I need a feature like the one described in http://www.pragma-ade.nl/gen eral/magazines/mag-1102-mkiv.pdf for annotated verbatim, but for normal text. Think about the main text flowing in a narrower text, with the annotations (like unnumbered sidenotes) in a widened right margin. Or think about a right margin moved left locally, as long as you need annotated text. Thanks, Massi