Hi Ramunas,
Have a look at transaction KKR0, you can maintain hierarchies for summarization reports, also classification characteristics can be used in the summarizations. But you probably need to identify first a formal logic.
It is not something flexible where you can build an hierarchy manually and rearrange it. Normally it will be based on some master data field. In some standard reporting you can take a view based on the Cost Center Hierarchy or Person Responsible (check DB profiles).
Regards,
Paulo