All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
When there is more than one funeral, the Shafie scholars are of the view that it is permissible to perform one funeral prayer for all. However, it is better to perform a separate funeral prayer for each. "When there is more than one funeral, it is better to perform a separate funeral prayer for each. But, if it was feared that the bodies could start decaying because of the delay, then it is better to perform one funeral prayer for all."{Umdat As-Salik, 92}.
If one funeral prayer was performed for all, and the bodies weren`t of the same group, such as a boy, a man and a woman, then the man is placed in front of the Imam, then the boy, then the woman. If the deceased were all men or women, then the most righteous of them is placed in front of the Imam. Ash-Shirbini said, "If there is more than one prayer, then a coin is tossed between the guardians of the deceased, then the man is placed in front of the Imam, then the boy, then the female intersex, then the woman. If all of the deceased were men or women, then all of them are arranged towards the Qibla and the most righteous is placed in front of the Imam."{Moghni Al-Mohtajj, 2/31}. And Allah knows best.