Hi Surya,
I just gone through your thread and surprised to see your requirement which was not clear to me. if i understood correctly ,
first and foremost thing is all company codes under the Controlling Area must have same Fiscal year variant and same Chart of accounts.
if this is in your case than activate parallel ledger for company code and assign the other FYV in the parallel ledger
and finally as you know we should maintain different number ranges for parallel ledgers for tracking.
I hope the above information helps you.
Regards,
Sree