How to default the tax registration number while importing AR invoices through FBDI

Summary: We have a situation in which there 3 different Tax regimes, each with the same tax registration number, under the same LRU. While importing AR invoices through FBDI, user want to default the tax registration number to a particular regime. We have already marked the default tax registration in the Manage Tax Registration setup, however, the invoices are not defaulting to the correct regime.

Version (include the version you are using, if applicable): 25A