Hidden related terms

We use this module to index a bibliography. Ideally, we would like to have related terms for each taxonomy term that are not visible. In other words, we can have the common name for a species appear in the taxonomy but have the scientific name, another common name, and a variant spelling of the species listed as hidden fields for that taxonomy term. When a user searches for one of the related terms, the visible taxonomy term and all records tagged with that term are retrieved. Does anyone know of a way to accomplish this?