Hi Faizan,
Have you tried Business Area concept for your requirement. Since your requirement is to follow external reporting requirement, therefore, you may not go for Profit Center Accounting. Review the following link to under the Business Area and Profit Center.
http://help.sap.com/saphelp_46c/helpdata/en/78/32868b88fa11d29c600000e8a51c6e/content.htm
I hope this will help you to decide.
Thanks,
Naseem