The Ruling on Collective Dhikr After the Prayers

Your Eminence! You said: It is permissible to raise the voice in dhikr after the prayer, but if this leads to the dhikr being done collectively by the worshippers, is that permissible?

I actually did not say: It is permissible! In fact, I said: it is a recommended practice (sunnah),Meaning: the best thing, for it is a recommended practice (sunnah) without doubt.
As for performing this dhikr collectively, that is a religious innovation (bid'ah); because the Messenger (peace and blessings be upon him) and his Companions did not do that. Each one would recite his dhikr for himself, but they would recite it aloud.