How to derive the First Party Tax registration number on the AR transactions

Hi,

Within our R12 EBS environment there is a single legal entity with multiple Tax Regimes. Our company is registered in country A (The Netherlands) and has additional registration with a local tax authority in country B (France). So when I have a transaction for Tax Regime A I want to derive the country A TRN (Tax Registration Number) and when the transaction is for Tax Regime B, I want to derive the TRN from country B.

How should the tax registration number of the first legal entity be set up in Oracle EBS? I have searched within the 'Tax Managers' responsibility and tried to explore the legal entity setup. But I don't know if I first need to create an additional establishment or not. Please help, as I think our setup is not okay.