[NTG-context] Is there a way to centrally add a list of indexed items to a sub category?

I have a document like this:     \starttext         \index{dogs}                  \index{cats}                  \index{flowers}                  \index{snails}                  \index{trees}                  \placeindex              \stoptext      As I understand, if you use \index{animals+dogs}, it will place dogs as a sub-category of dogs. Is there any way to control this centrally, for instance: \addtosub[animals]{dogs, cats, snails} \addtosub[plants]{flowers, trees} Such a way would make it so \index{dogs} places an entry for "dog" under "d" and "animals --> dogs" under "a". --Joel