Need to Map Supplier Registration DFF to Field on Supplier Details

We have the requirement to add a field from a Supplier's Address onto the External Supplier Registration form. From searching for a Supplier → Addresses → Select an Address Name → Transaction Tax → Tax Registrations → Tax Registration Type is an LOV field that we want to capture earlier in the process.

Under the setup "Manage Supplier Registration Descriptive Flexfields" I have made a new DFF, and created a Value Set to have the same options as the preciously mentioned field from a Supplier's information.

Now, it is required that the response entered in this DFF be mapped into the Tax Registration Type field. Is this achievable? Perhaps when creating the DFF there is a step at the start to map it to a downstream field? Any input here would be much appreciated. In short: