"And it is upon those (relatives) of the killed one to block (any punishment) the first (in line) then the first, even if that one is a woman." (Using translation from Nasāʾī 4788)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «وَعَلَى الْمُقْتَتِلِينَ أَنْ يَتَحَجَّزُوا الْأَوَّلَ فَالْأَوَّلَ وَإِنْ كَانَتِ امْرَأَةً»