Assalaamu alaykum. Can two masjids with only two houses between them perform the Thuhr prayer at the same time?

All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

The prayer is valid if it is held in both masjids at the same time provided that external loudspeakers should not be used in order to avoid the interference of sounds. The Prophet, sallallaahu ‘alayhi wa sallam, said, "...and none of you should raise their voice in recitation over the voice of the other." [Ahmad and others]

To start with, there should not be two masjids at a close distance to one another without a need, because this would disperse the community of Muslims and cause neglect of some of the very objectives for which the congregational prayer was prescribed. Scholars stated that it is prohibited to build mosques next to each other.

Kashshaaf Al-Qinaa‘ (book) reads:

"It is prohibited to build a mosque next to another mosque except for a need, such as is the case if the first mosque is not wide enough to accommodate all the worshipers of the community and the like or if it is feared to incur Fitnah (temptation, tribulation) by their gathering in the same mosque. This ruling (the prohibition) apparently applies even if the second mosque was not built for the purpose of causing harm (driving the worshipers of the first mosque to abandon it and pray in the new one instead, leaving the first mosque empty and deserted as a result). Al-Muntaha reads: It is prohibited to build a mosque next to another if the purpose of building it is to cause harm."

It was narrated that ‘Umar forbade building two mosques close to one another. Tuhfat Al-Ahwathi reads:

"Al-Baghawi reported from ‘Attaa' that when the Muslims conquered vast territories during the rule of ‘Umar he commanded the Muslims to build mosques and instructed that no two mosques should be built next to each other for the purpose of causing harm by disuniting the Muslims. If there already is a mosque in the neighborhood, then it should be expanded to accommodate all the worshipers, or another mosque may be built that is wide enough to accommodate all of them."

Scholars censured building many mosques in the same neighborhood and considered it a religious innovation. Jamaal Ad-Deen Al-Qaasimi said:

"As-Suyooti wrote in his book Al-Amr bil-Ittibaa‘ wa An-Nahi ‘an Al-Ibtidaa‘, 'One of these religious innovations is building many mosques in the same area as it causes disunity, dispersing the worshippers, breaking up the congregation, undermining the beauty of worship in a large congregation, severing the ties between the worshippers and causing them to go separate ways. In addition, it contradicts the very rationale for which the congregational prayer at the mosque was prescribed to begin with; namely, establishing the unity of the Muslims in performing the acts of worship, exchanging mutual benefit and help. It also leads to harming the old mosque or at least causing inconvenience to it, seeking fame and admiration, and the wasteful disposal of wealth in what is not needed.'" [Islaah Al-Masaajid min Al-Bida‘ wa Al-‘Awaa'id]

Allah knows best.