In this configuration activity you are able to define dunning areas. They could be used for separating the dunning procedures on different groups of customers.
IMG Path: Financial Accounting (New) -> Accounts Receivable and Accounts Payable -> Business Transactions -> Dunning -> Basic Settings for Dunning -> Define Dunning Areas
Tables: T047M, T047N
When you open the transaction you will get a list of predefined dunning areas. From her you could create new or modify an already existing one.