Hi Hermann,
Do you require consolidated balances at each group or it is just a presentation?
If you require a consolidated balances (after interco elimination) at each group level, then you have to enter the POWN/PCON/PCTRL as the case may be and then only you can generate the consolidated balance at that group level.
and if it is just a presentation, then change your entity structure to rearrange the entity based on reporting and maintain normal ownership. For report, you can then use the entity hierarchy. (assuming that the no intercompany balances are required to eliminated for each group)
Regards,
Rahul