[NTG-context] marks on the first page only

Hans, would it be possible to have a "first" value added to the "marking" key from \setuplayout that prints cut marks only on the first page of the document? In some cases, having cut marks in all pages is unnecessary. Or even unpractical, because some printers slightly move the marks when printing (they don’t print the text exactly on the same position on each page [it happens in most copyshops]). I would need this for the imposition I asked about yesterday (https://mailman.ntg.nl/pipermail/ntg-context/2016/087038.html). Sorry for insisting, but I need to solve the issues for something I have to send to a copy shop today. Many thanks for your help, Pablo -- http://www.ousia.tk