Muhaqqaq Masala

It is better and recommended that every time the blessed name of the Holy Prophet ﷺ is uttered, the one who utters it and all the people who hear it send Durood and Salam upon him ﷺ. However, if in the entire gathering, even a few people say "Sallallahu Alaihi Wasallam" upon hearing his blessed name, then in this case, its obligation is waived for the others. Whereas, during the entire gathering, it is obligatory (Wajib) to recite Durood and Salam at least once upon the blessed name of the Prophet ﷺ, and negligence in this is a cause for punishment. (Aham Masail / Vol: 10 / Pg: 45)