[NTG-context] [startstop]

I'd like to create a start/stop command with a parameter \startzzz[a] one two three \stopzzz \startzzz[b] one two three \stopzzz How do i define/pass the tag parameter in the definition? This does not work (obviously) \definestartstop[zzz][ before={\hrule\bf tag\blank}, after={\blank[10mm]} ] I cannot find it in the documentation .F