Musannaf Ibn Abi Shayba 19:123

Abu Bakr narrated to us, he said: 'Abdah bin Sulayman narrated to us, from Sa'id, from Abu Ma'shar, from Ibrahim, regarding a man who accuses a group of people collectively with a single accusation: He said, "Upon him is one prescribed punishment (hadd)." And Qatadah said, from al-Hasan: "For every man among them is a prescribed punishment (hadd)."