So long as prayers are offered in the mosque, the Sunnah is for the adhaan and iqaamah to be given there. Even if you have heard the adhaan of the other mosque, in most cases the other mosque is far away, especially with these loudspeakers which enable them to hear one another. The Sunnah is for the adhaan to be given in each mosque, and for the iqaamah to be given in each. Whoever hears the adhaan from any mosque has to respond to it. End quote.
Shaykh ‘Abd al-‘Azeez ibn Baaz (may Allah have mercy on him)