Somalis are Cushitic people. You have to have majority Cushitic [native to the Horn of Africa] ancestry to be Somali.
Bantus are genetically from Nigeria. Their ancestry is completely different. A pig born in a stable does not make it a horse.
Dr Amun, the Bantu have already mixed with several clans and you know it too. You need to give up on this dream of yours. You will never have a pure Cushitic state.