[xwiki-users] Help with database list classes

Hi all, I'd like a property in a class to represent a list of all users, plus an "unknown" option so that the field can be left "blank" if required. I can get the list of users with the hibernate query: select prop.value from BaseObject as obj, StringProperty as prop where obj.className='XWiki.XWikiUsers' and prop.id.id = obj.id and prop.id.name='fullname' order by prop.value But don't know how (or if it's possible) to modify the query to append an extra static value like "unknown". I would rather not create a dummy user to represent this value, and if I can avoid creating a separate dummy class and object to hold the value that would be good too. If the list class could understand velocity arrayLists rather than the hibernate query, I could do something like: ### Select all users: ### #set($query = "select prop.value from BaseObject as obj, StringProperty as prop where obj.className='XWiki.XWikiUsers' and prop.id.id = obj.id and prop.id.name='fullname' order by prop.value") #set($users = $xwiki.search($query)) ### append an extra value: ### #$users.add("(unknown)") Is there a way to modify the hibernate query to achieve the same effect directly in the class editor? Thanks, Robin.