Hi Carlos,
You could display better than only one displayname! You could display both separated, the artist and the gallery, if the relationship types between occurrence and entities are correctly qualified.
By "qualified relationship", I mean that the type of link between the occurrence and the entity can be specified, like for example: artist, gallery (and not just a default link like "is related to").
By doing this, you can easily view the information separately on the occurrence detail page.
Let's suppose that the relationship type identifiers are: artist and gallery.
(You can define this in MANAGE > ADMINISTRATION > RELATIONSHIP TYPES, in "entity ⇔ occurrence relationships". Default is "related", and there you could add some other types, like "artist" and "gallery".)
Then, in the detail page ca_occurrences_default_html.php, try to add this:
{{{<unit relativeTo="ca_entities.related" restrictToRelationshipTypes="artist">
<p>Artist: <l>^ca_entities.preferred_labels.displayname</l></p></unit>}}}
{{{<unit relativeTo="ca_entities.related" restrictToRelationshipTypes="gallery">
<p>Gallery: <l>^ca_entities.preferred_labels.displayname</l></p></unit>}}}
