If you have more than one company code and all the company codes are using different operating chart of accounts (COA) then cross company code controlling will not be possible by using controlling area.
To avoid this problem one can use group COA. A group COA is used for consolidation purpose when more than one operational COA is used by different company codes. Group COA is helpful for internal reporting.
To use Group COA you need to assign it to the Operating COA of a company code. When you assign it, Group A/c Number field in the COA segment of the operating chart of account (COA) becomes a mandatory entry. The group COA must contain all the group A/cs to get it entered while creating a general ledger master in operating COA.
You can also assign one A/c of a group COA to more than one A/c of an operating COA.
To get it consolidated you should define a separate financial version for the group chart of account.
The only disadvantage in group COA is, you can not have cross company code controlling. If you want to have cross company code controlling then the best option is to have one operating COA for all the company code and those company codes require special COA can get assigned to country specific COA.
The country specific COA number is entered in the company code segment of a general ledger A/c master in the field “Alternative Account Number”. Each country specific COA number can only be used once.
A combination of group Chart Of Account, country specific COA, operating COA and cross company code controlling can be used in SAP.
COA should always be decided with the business process owner before its implementation. As changing COA after implementation is not possible. SAP financial consultant and financial business owner from the business side should sit together and decide its COA.
After deciding the COA you need to consider the general ledger account and accounts groups to be created within it. If you take a decision before its implementation then things will be easy and clear.