Add Validation Rule on Supplier Registration Page In Oracle ERP Cloud

Hi,

I have a requirement to add a validation rule on the Supplier Registration Page to force end users to enter any of DUNS Number or Taxpayer Id or Tax Registration Number OPTIONALLY depending on the selected Tax Country. There is available from "'Configure Supplier Registration and Profile Change Request'" to COMPLETELY disable the validation on these Fields, but that wouldn't work for the current requirement, we want to optionally enable the validation over these fields.

Moreover, I tried to search in the application composer if I could add any validation rule on this page, but I didn't find any standard object for "Supplier" or "Vendor".