Does anyone has an idea for the situation below?

Situation:
We need to send e-invoice invoices (XML) to our customer in Belgium. For this, four customers have been created in IFS, even though it actually concerns one legal entity with one VAT number.
The customer database in our set up in IFS is based on DUNS (credit agency nrs): for each unique DUNS number a customer is created. In other words, each location/branch of that customer has been assigned a separate credit agency number, although it is same entity