What is the ruling if there are several groups of congregations in the same praying space?
I’ll divide it into two locations which are the mosque and surau or surau in shopping complexes, R&R areas and others similar to them.
Mosque here means the official mosque that is prepared for the congregation to perform the five obligatory prayers, the Friday prayer and others with its own specific official appointed imam (imam ratib). This also includes the normal surau and surau where Friday prayer is performed with the previously described characteristics.
Imam al-Ramli explained: “It is makruh to perform congregation prayer in mosques other than the place where a lot of people pass through which has its own imam ratib (official) without his permission whether (the congregation is formed) before, after or at the same time with him (concurrently). If the imam ratib isn’t there then it is sunnah to wait for him (to perform the prayer).” 
For surau in shopping malls, R&R areas, KTM stations and others or are also called in classical fiqh as al-masjid al-matruq, Imam al-Ramli said: “As for a mosque in an area where there a lot of people passing through, then it isn’t makruh to have several groups of congregations. This includes a mosque that has imam ratib. (And it isn’t makruh) to have two congregations that prayed simultaneously in it.”
Hence, generally, it is permissible to have several groups of congregations praying concurrently in suraus in shopping malls, R&R areas, KTM stations and others similar to them except in a mosque, then it is makruh. The reason is they don’t have an official imam nor the characteristics of an official mosque. However, there is a great advantage to performing prayer in congregation, as well as the need to showcase the eminence of Islam and unity of Muslims as well as preventing confusion when there are several imams at the same time. Thus, it is prioritized to perform congregational prayer with just one imam. Wallahu a’lam.