Musnad Ahmad 152:2

Rawh narrated to us, Shu'bah and Malik ibn Anas narrated to us, from Yahya ibn Sa'id, from al-Qasim ibn Muhammad, from Salih ibn Khawwat, from Sahl ibn Abi Hathmah, and he mentioned its meaning, except that he said: "He prays with those who are behind him one rak'ah and two prostrations, then he remains sitting in his place until they complete one rak'ah and two prostrations. Then they move to the position of their companions, and then their companions move to the place of these ones," and he mentioned its meaning.