Is it permissible to give zakat to orphaned sisters who receive a partial pension?

It is permissible to give Zakat (definition) to poor sisters whose income is insufficient for their needs, because it is both charity (sadaqa) and an act of maintaining kinship ties (sila), as stated in the noble Hadith (definition): "Charity given to a poor person is charity, and to a relative, it is two: charity and maintaining kinship ties." As for wealthy sisters, it is not permissible to give them Zakat, because Zakat is only given to the eight categories mentioned in the verse from Surat At-Tawbah (definition).