[NTG-context] Produce multiple versions in one run

Hi, let's say I want to produce two different versions of my document, one with papersize a4, the other with papersize a5. ``` \setuppapersize[a4][a4] \startmode[a5] \setuppapersize[a5][a5] \stopmode ``` What is the best way to produce both versions with one command? A makefile? Or is there a way to do this with context alone? Best, Denis