[NTG-context] different preffixsegments for different reference formats

Dear list, I have the following sample: \starttext \definereferenceformat[itsc][in] \setupreferencestructureprefix[itsc][default] [prefixsegments=section] \chapter{Chapter} \section[b]{Section} \itsc[b] and \in[b] \stoptext How can I get that \itsc gets "prefixsegments=section" without affecting to \in? Many thanks for your help, Pablo -- http://www.ousia.tk