From Ihyaud Deen. This entry is part 21 of 23 in the series Janaazah
If there are several Janaazah’spresent at one time, performing a separate Janaazah Salaah on each deceased is better. However, if one Janaazah Salaah was performed on all the deceased it will be permissible.
Upon which deceased should Janaazah Salaah be performed first
If each Janaazah is performed individually, then the Janaazah Salaah of the one possessing the most deeni virtue (the one possessing the highest rank in deen) will be performed first, followed by the one who is second in rank, and so forth.