The master records in the customer hierarchy are controlled by their account groups. You can use the same account groups for customer hierarchies as those used for partner determination in sales and distribution.First thing to understand, when talking about a Customer number in SAP, you are generally talking about a Business Partner record that has been assigned a particular account group which controls the information and functions that business partner can have.? Depending upon the account group assigned to a business partner, it can function as one or all of those partner functions for itself or any other business partner in your system.