Legal reporting unit for payables Invoices

In the context of India- We have one legal entity, 1 Legal reporting unit currently but now business needs to add new locations (ship to locations). Since each location has a separate GST number, we need to segregate the AP invoices for each location so we want to define the additional legal reporting units for additional locations but we don't see the LRU field anywhere on the Invoice header or invoice line level. Can you please suggest how to link the LRU to AP invoices or achieve this? We are not using the India localization.