[NTG-context] Custom cite commands

Dear all, I'm in need for a few custom cite commands like these: 1. \cite[alternative=authortitle, extras={, p.\,13}][citekey] should yield {\sc AuthorLastName}, AuthorFirstName, {\it title}, p.\,13 2. \cite[alternative=title][citekey] {\it title} How would I code these commands? Oliver