Account category structure
An account category structure is a hierarchical organization of all of the account categories you use to track costs and revenues for an activity group. It is made up of summary and detail account categories, and can contain multiple types of account categories.
Account category structure is assigned to an activity group in Project Accounting. All activities in an activity group can then post to the account categories in the structure. You can assign the same account category structure to more than one activity group, or you can assign a different account category structure to each activity group.
This diagram is an example of a simple account category structure: