Hawzah News Agency – Can one say one’s congregational prayer behind a Sunni Imam with the intention of Jama'at (congregation)? And should one recite al-hamd on his own?
Answer: it is permissible to offer prayer in their congregational prayers, in areas where Taqiyah (dissimulation) is required. However, it is obligatory upon you to recite al-Hamd and the second chapter yourself – be the recitation in low voice though.
Source: https://www.sistani.org/