When preparing consolidated financial statements for a group with a complicated hierarchy, you can choose to use either simultaneous or step consolidation. In the latter case, the companies are consolidated step by step in accordance with the group hierarchy.
Basically, you have to create a separate subgroup for each hierarchy level, consolidate it (simultaneously) and transfer the results of the consolidated to a roll-up company. This roll-up company is then rolled up into the subgroup at the next hierarchy level and is treated as any other company. You repeat this procedure as often as necessary until consolidation is carried out at the highest level.