Praise be to Allah.wa alaikum us-salaam wa-rahmat ullaahi wa-barakaatuh
It is permissible for women to pray in congregation among themselves. Their leader should stand in the middle of the row according to the narration regarding Aa’ishah (may Allaah be pleased with her) which indicates that she used to lead women in prayer and would stand with them in the middle of the row. This has been narrated by ‘Abdur Razzaq in Al-Musannaf 3/141 and Daraqutni 1/404, and is authentic due to evidences for it.
Similarly Umm Al-Hasan narrated that she saw Umm Salmah (may Allaah be pleased with her) leading women in prayer while she stood in the middle of their row. This has been narrated by Ibn Abee Shaybah 2/88 and is also authentic due to other supporting evidences.
Ibn Qudamah has quoted the difference of opinion on whether congregation for women is recommended, and then says about their leader: “The one who leads them should stand in the middle of the row. We do not know of a difference of opinion on this among those who support that one women may lead others in congregation. Since it is recommended for the women to be covered, ….. standing in the middle of the row makes it a better covering for her from the sides.”(Al-Mughni, 2/202)
The author of Al-Muhadhdhab (4/295) says: “It is sunnah that the leader of women in congregation stand in the middle of them as narrated about ‘Aa’ishah and Umm Salmah that they lead women and stood in the middle of their row.”
For further details refer to Jaami‘ Ahkaam Al-Nisaa’ by Al-‘Adawi (1/351).
And Allaah knows what is most correct and best.