الجواب وبالله التوفيق

The answer to your question has detailsdepending upon:

• If the mosque is in the bazar
• If the mosque is in a mohalla(residential area)
• Whether the time of salahis fixed and the imamand moazzin are specified

The ruling for each of the above mentioned situations are different. 

Regarding 1&2, if the mosque is situated in the bazar and the timing for salah is fixed, and the imam and moazzin are specified then making second Jamat there will be considered absolute makrooh. The same ruling applies on the mosques in residential areas. The mosques which are situated in bazars but the timing for salah is not fixed and the imam and moazzin are not specified then it is permissible to perform second Jamat in such a mosque. Therefore, in mosques in the residential areas or such mosques in bazar where the timing for salahi s fixed and the imam and moazzin are specified, making second Jamator multiple Jamats habitually (without a legitimate reason) and leaving the actual Jamat in the mosque is consider a sin

عن عبدالرحمن بن المجیر قال دخلت مع سالم بن عبداللہ مسجد الجمعۃ وقد فرغوا من الصلاۃ، فقالو: الا تجمع الصلاۃ فقال سالم لا تجمع صلاۃ واحدۃ فی مسجد واحد مرتین  (کتاب النوازل ص 501، ج 4 اعلاء السنن)

(ویکرہ تکرار الجماعۃ باذان واقامۃ فی مسجد محلۃ  (کتاب النوازل ص 508، ج4، بحوالہ در مختار

(مسجد لیس لہ موذن وامام معلوم یصلی فیہ الناس فوجا فوجا بجماعۃ  (کتاب النوازل ص 509، ج4 بحوالہ شامی 

واللہ اعلم بالصواب