Every day I set aside some money as sadqa. Once accumulated to a reasonable amount, I donate it. Last month I gave it to my in-law family because of their financial situation.
Yes it is permissible to give Sadaqa to poor Sayyeds as far as the Sadaqa is not obligatory. If it is obligatory like Fitra or Zakat, then it is not permissible for Sayyed to receive it from Non Sayyed, and not permissible for Non Sayyeds to give it to poor Sayyeds.