Asalam alaikum.I want to ask whether the concept of jammat in islam is proved according to sunnah or not.by jammat I mean,people including men and women who leave their house and go to other cities.men stay in mosques and women stay in someone house.they make food by mutual help.they do all the izkar,pray all namaz including tahajud and ishraq and recite quran.but my point is, if an alim is in the jammat then common men and women are benefited by his/her knowledge.if no alim is present then what is the use of sending jammats to other cities? Is this amal a biddat?