Girls Planet 999 Episode 6

The episode begins with the 54 girls entering a room. Host Yeo Jin-goo then enters the room, explaining that the next mission would be the Combination Mission. He also reveals that cells will be disbanded and cell votes will be phased out, meaning that rankings are all now individual. He then moves on to explain the Combination Mission, stating that the 54 girls will be split into either 3-member, 6-member or 9-member teams for the mission. There are a total of 6 songs for 3-member teams, 3 songs for 6-member teams and 2 songs for 9-member teams. To determine their teams, the girls enter doors labeled "3", "6" and "9" which will lead to respective 3-member, 6-member and 9-member team songs where they will have to pick which song they want to perform. After forming their teams, the girls then proceed to prepare for their group performances. The girls are first evaluated by the mentors through an interim check before the actual performance. (Source: Kpop Wiki)