For somewhat similar issues, I've created a new entry, copied the existing entry to it, and modified the new entry.
Roughly something like this - I'm a bit slow at the moment so i may have made a mistake.
Code:
[defaults]
## Creates an entry for use in the title-pages. Leading comma is because it concats to existing entries.
add_to_extra_valid_entries:,titlepage_ships
## This adds the existing ships to the new category.
include_in_titlepage_ships:ships
## Now you can run include, exclude, or replace_metadata on your titlepage_ships without it affecting the main one.
replace_metadata
titlepage_ships=>whatever=>some ship
exclude_metadata_post:
titlepage_ships==some ship
## Now send that to your column.
custom_columns_settings:
titlepage_ships=>#covercolumn