is Billy the only one of them now...

Originally, in the comics, the Justice Society of America was from the Golden Age. generally 1938-1956. It gathered several of the various super heroes. The founding members were Dr. Fate, Hour-Man, Sandmand, Spectre, Atom, Flash (the Jay Garrick version), Green Lantern (the Alan Scott version) and Hawkman (the Carter Hall/Egyptian Prince version.) The was also a brief appearance by Red Tornado (the Ma Hunkel version, though she never appeared again.)

Later, it was retconned that Batman, Wonder Woman, and Superman were honorary, founding members.

In 1957 the Silver Age of Comics began. New versions of many heroes were created and some disappeared. The concept of the Justice Society was revived, but called the Justice League of America. The founding members of the Justice League were Superman, Batman, Wonder Woman, Flash (Barry Allen version), Green Lantern (the Hal Jordan version), Aquaman, and the Martian Manhunter.

Over time, DC comics thought it would be fun to do a team-up between the JSA and JLA. So they decided that the JSA was the super team from Earth 2, a version of Earth existing in a parallel dimension. (multiverse, anyone?). The JLA was the version from mainline Earth, called Earth 1. For a number of years, there were yearly teamups of the JLA and JSA.

Note that the there were considerable differences between the two Flashes and Green Lanterns in costume and, to a lesser degree, powers. The Earth 2 variants of Superman, Batman, and Wonder Woman were largely identical and did, on occasion, appear in the team-ups.

When the Crisis on Infinite Earths occurred and all the multiverses were collapsed into one, it was set that the JSA was the earlier group and was founded during WWII. Later, in the "modern era," the JLA came onto existence and the presumption was that the JSA had disbanded. (there were stories that delved into that.)

continued next post.