Hello,
the object result list can be configured by creating a search scope for the custom object.
See: https://technet.microsoft.com/en-us/library/ff393653(v=ws.10).aspx#bkmk_search
But if I remember correctly only the default "DisplayName" will get the hyperlink function to click on to see object Details, so you should always fill the default "DisplayName" also.
Regards
Peter