Reference: al-Bid’u wal-Muhdathaat wa maa laa Asla lahu – Page 394
Fataawa al-Lajnah ad-Daa.imah lil-Buhooth al-‘Ilmiyyah wal-Iftaa. – Question 4, Fatwa No.5609
Question: What is the ruling regarding the pilgrims making talbiyah as a group [in chorus], whereby one of them makes the talbiyah and the rest follow him?
Response: This is not permissible for the non-existence of any evidence from the Prophet (sal-Allaahu ‘alayhi wa sallam) and nor from any of the Rightly Guided Khulafaa (Abu Bakr, ‘Umar, Uthmaan and ‘Alee (radhi-yAllaahu ‘anhum)). Rather, it is an innovation.
And with Allaah lies all success and may Allaah send prayers and salutations upon our Prophet (sal-Allaahu ‘alayhi wa sallam) and his family and his companions.