[NTG-context] Ordered list of references (figures)

Hi wizards, in my current book projects I need a list of figure references, ordered by author and page number. Like this: Photos: Hans Hagen (p.1,4,6,7), Taco Hoekwater (p.2,12–20), Hraban Ramm (p.3ff.) How can I do that? I.e. - How can I assign an author name/reference to a figure? – How can I output that list? About like this?: \placefigure[top][someref]{\externalfigure[somepic]}\reference[someref]{Hraban Ramm} \ref[t][someref] (\at{p.}[someref]) % put this in some command that is called by \listoffigures ? Extension: I need to integrate some unnumbered pages into the list, like the cover. Greetlings, Hraban --- http://www.fiee.net http://wiki.contextgarden.net https://www.cacert.org (I'm an assurer)