Is dedication of property (Waqf) valid when designated for a large tribe or community?

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Dedication of property is valid when stipulated for a great tribe, such as Quraysh, Banu Hashim, Banu Tamim, or Banu Wa'il, and similar groups. It is permissible to dedicate property for all Muslims, or for the inhabitants of a province or city, like Al-Sham or Damascus. A man may dedicate property for his clan or the people of his city. The basis for this validity is that dedication is sound if the designated recipients are countable, and it remains sound even if they are not countable, such as the poor and needy. Furthermore, if the dedication is for those whose number cannot be enumerated, no single beneficiary owes Zakat on what is rightfully theirs from the dedication, nor does the whole dedication incur Zakat.