Group B's Maze Trial
From The Maze Runner wiki
It was revealed in the story that WICKED in fact conducted two experiments, with more than one maze. The Maze Trial for Group B was extremely similar to the Trial for Group A (The Gladers), with minor differences. It is said to be an alternate, where instead of boys, girls take their place. The members of Group B escaped their maze three days earlier than the counterpart, suffering less casualties and killing more Grievers.
Characters
The Trial
Everything in Group B's trials was the sames as Group A's before they escaped. The only difference is that Rachel, Thomas' Group B equivalent, was killed by Beth because there was no Chuck equivalent to save her like Thomas. This makes Thomas believe he should have died instead of Chuck.