Alternate song number (custom song ID) or change of "CCLI number" field to distinguish non-CCLI songs

We need another "alternate song number" or "custom song id" or some such field to include our OneLicense song number for songs from OneLicense versus CCLI.
Or otherwise allow us to use a non-number (text id) in the "CCLI number" field to distinguish between CCLI versus non-CCLI songs? (eg. We might insert the "#" character in front of the OneLicense song number as a text character distinguishing CCLI versus OneLicense, or we might otherwise use the text "OneLicense #1234345" or some such)
Or alternatively, or in the interim, can we maybe also export the "Copyright" field? Then we could put our OneLicense song numbers in there. That would be better than the "Artist" field for this purpose.