Sudhanvan said Father and son, two Brahmanas, two Kshatriyas, two old men and two Sudras can sit together. Excepting these, no others can sit together.
सुधन्वोवाच पितापुत्रौ सहासीतां द्वौ विप्रौ क्षत्रियावपि। वृद्धौ वैश्यौ च शूद्रौ च न त्वन्यावितरेतरम्॥