Is supplicating for the deceased and saying "Ameen" after burying them from the Sunnah?

Sheikh Ibn Baz issued a fatwa permitting communal supplication for the deceased after burial, where one of those present supplicates and the others say 'ameen' to his supplication, or each person supplicates individually. He based this on the action of the Prophet, peace and blessings be upon him, who would stand at the grave after burial and say: "Seek forgiveness for your brother and ask for steadfastness for him, for indeed he is now being questioned." The more preferable and closer to the Sunnah is for each person to supplicate individually, as Sheikh Ibn Uthaymeen clarified that communal supplication is not from the Sunnah of the Messenger of Allah, peace and blessings be upon him, nor from that of the Rightly Guided Caliphs.