Hi Khan,
I think your are going right way.....but check once again concept of the group chart of account and mappings....
first, you have to create the new chart of accounts in table T004 (transaction OB13). Then, in the same transaction, enter the new group CoA for your operational chart(s) of accounts, field T004-KKTPL.
As a result, the field group account number (SKA1-BILKT) in your operational chart of accounts will become mandatory. Of course, you need to create some group accounts, transaction FSP0, in your group chart of accounts first.
The T004 entry for the group chart of accounts is quite basic, and I would recommend not to overcomplicate T077S (account groups, transaction OBD4) neither.
One account group should be enough, and you do not have to worry about field status - group accounts are only created on chart of accounts level, so the company code level fields are not relevant at all. (Unless your group CoA is used by other company codes as an operational CoA).
Further impacts: the group account number can be changed even if there is a balance on the operational account in at least 1 company code.
This may lead to a faulty balance sheet. Message FH 167 can be changed to error (default is warning) if you like (see table T100C).
Also, you may need to add a new financial statement version (T011, transaction OB58) having the group accounts from the group CoA assigned.
For this financial statement version, you should tick the corresponding flag on OB58 (T011-XERGS).
Thank you.
Regards
vamsi