[NTG-context] formatting index entries

Dear list members, In my book I am creating an index. I know that there are commands for formatting index entries, like: \index{sl::īga} if I want the word 'īga' to be printed in slanted type. I also know that we can create sub-entries, like \index{īga+emphasized} But now I want the word 'īga' to be slanted, but not the word 'emphasized'. I have tried things like \index{sl::īga+rm::emphasized}, but I can't figure this out. Any suggestions? Robert