If the name::_id mapping isn't unique, you need to build a model or view that provides a 1:1 mapping between a display name and _id (append the _id to the name or something). Join that model or view to your query to map the filter name.
EDIT: Another option -- Metabase may actually know how to do this internally. Set the _id field as an Entity Key an the name field as an Entity Name in the table metadata and use a field filter -- Metabase may do the mapping for you. It was discussed in this thread: