Can be thought of as semi-autonomous communities with fairly informal leadership, but which have cross-cutting kin groups or associations which allow them to occasionally integrate into a larger unit.

tribe or tribal organization

Explanation:

Tribe is a human social group or an organization in which local communities act in an almost autonomous way, but there are kins or associations which integrate kin groups into larger units. It is a small community with informal leadership, nomadic or semi-nomadic and headmen.

the density would be a smaller number.

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