I have an index like this:

\starttext
\index{butterflies}\index{horses}\index{cows}
\placeindex

\stoptext
The placeindex will place every index.
Is there a way to say, display an index, but only for a specific single entry, or specific list of entries, e.g.
\placeindex[horses, cows] (would exclude butterflies from the index entries)
--Joel