[NTG-context] \includeonly and ConTeXt components

Hi again, last question for the moment ;-) With LaTeX we can use `\includeonly` for partial compilation. The good thing is that we can still refer to labels from other files, have a complete TOC, and correct page numbers. In ConTeXt the project structure is supposed to be used for partial compilation. But it does not seem to have those features, right? Having correct page numbers across the individual components would be especially helpful. Any ways to get this? Best, Denis