What is the ruling on communal Talbiyah in the bus if individual Talbiyah is not possible? Is this considered a necessity that permits it, to prevent discord? Should the pilgrim remain silent if he cannot perform Talbiyah except with the group, or should he perform it with them?

The collective Talbiyah is an innovation (bid'ah) that was not transmitted from the Prophet, peace and blessings be upon him, nor from his Companions. However, it is permissible if the voices of those performing the Talbiyah happen to coincide unintentionally. The pilgrim should perform the Talbiyah and raise his voice, but if he fears a harm, he should lower his voice. He should not stop performing the Talbiyah, because it is one of the rituals of Hajj and among the things the Prophet, peace and blessings be upon him, commanded to raise the voice with.