[NTG-context] \godown to an absolute position

Hello. I have a style request that I haven't come across before and don't know how to handle in ConTeXt. I need the first line of text following a chapter title to always start 15 picas from the top edge of the text area. In other words, no matter how little space the title takes up, the first line after it should always start at the same vertical point. Something like -- \chapter{Chapter title} \godown[to=15pc] Start of the text of the chapter... -- would be ideal, but of course \godown starts from the current point and doesn't offer a to= option! I'm not sure that layers are the answer because as soon as I have moved down I'm into the running text of the chapter. Can anyone help? Thanks very much. Duncan