First, make sure that you are worship Isis, then when advancing into the Mythic
age, worship Osiris, then research New Kingdom at the temple, usethe "divine 
intervention" cheat on the Son Of Osiris god power and use it on both of your
pharaohs. Then, wait about a minute, and you will get another pharaoh. Use the
Son of Osiris god power on it, and repeat the process as many times as you like!
(Don't forget to keep using the "divine intervention" cheat for the Son of Osiris
god power.)