FDM.2:4.2 - State why these members belong together
State the question the grouping serves and its inclusion criterion. The criterion may concern a common founder, control, contractual support or inclusion in the consolidated accounts under the applicable reporting rule. Establish membership at the time relevant to that question. Preserve the underlying positions when a group view is produced.
Different criteria can produce overlapping groups. Keep them connected when the receiving use needs them. A single hierarchy need not carry every financial relation.