I'd like to sort my database of photos using a reference field. The reference field belongs to another database of individuals. How can I sort my photos in the database so they are grouped by the individuals of the reference field (and thus allow me to work on them 'backstage' in the database, putting them in order and giving them captions etc)? The sorting and filtering options given for the reference field are only to sort or filter by whether or not the field is empty, as far as I can see. Ideally I'd like to sort the database so that it is arranged alphabetically by the individuals the photos belong to.