Hi Ephraim,
you can create a custom rule and then change the classifier rule for that property, though on upgrade you'd probably have to change it again since you're re-using an existing field. I'm not sure what the South African ID looks like but you should be able to do similar type pattern matchings and such. Happy to help if you share the general format?
-- Alex
https://docs.intersystems.com/hs20221/csp/docbook/DocBook.UI.Page.cls?KE...