Fan CastingJustice society of America vs justice society infinity

during the golden age of superhero's a group of costumed mystery men gathered together to form the justice society of America but one day a breach opens revealing a team of young superhero's who call them self justice society infinity there members are all legacy members of the jsa some of there children some not but they are looking for a mysterious man named superman who seems to be the cousin of the jsi's leader power girl but this is a long time before the name superman was ever uttered but the opposite team from earth 1939do not believe them and they fight each other until power girl accidently kills one of her team mates ending there battle whilst the flash explains to her that they are not lying about superman and creating a bond with her and the rest of the team and before they go home power girl gives Kent nelson a device that would allow him to travel to any universe that they want but he deems it to dangerous in the wrong hands and locks it in a vault in the tower of fate later to be stolen when Lex Luthor kills nelson in the post credit scene of the last justice league movie