How to add Northern Ireland (XI) VAT zone

We are a business in the EU, and we sell products to customers in the EU & UK, including Northern Ireland. Based on our official tax information website, it seems after Brexit – and for the next 4 years – sales to Northern Ireland customers must not be separated from sales to UK customers in our VAT declarations (VAT for Northern Ireland sales will be paid to the EU tax office rather than the UK tax office). It was suggested that we use the “XI” country code, but currently there are only “GB” and “IE” tax zones in WooCommerce. Is there a way to set up the extra XI geographical zone with this plugin?

Thanks!