Additional Copyright status

Dear fellow Lightroomers,

Is there any way to add an additional Copyright Status?  The software currently gives me Unknown, Copyrighted and Public Domain.  What I would like to add is: 'Out of Copyright' or 'Conditions of Use Apply'.  This status affects a considerable number of files that I am dealing with particularly from Australian Libraries (See https://www.slsa.sa.gov.au/no-known-copyright-restrictions) I would like a method of flagging up in the copyright that we need to acknowledge the use of these images.

Any ideas?

many thanks

David