Announced in the March 2016 FC newsletter, a new Engeki Joshibu musical titled "Zoku 11-nin Iru! : Higashi no Chihei, Nishi no Towa" starring Morning Musume. '16, Tsubaki Factory (Yamagishi, Ogata, Kishimoto, Asakura), and Kenshuusei (Hashimoto, Takase) and Ishii Anna and Onoda Ayasa. 6/11~6/26.
"Zoku 11-nin Iru! : Higashi no Chihei, Nishi no Towa" 続・11人いる!東の地平・西の永遠 (Continue, They Were Eleven! : Horizon of the East, Eternity of the West) is a sequel to a Shoujo manga called "11-nin Iru!" (They Were Eleven). There have been many stage play adaptations already.
https://en.wikipedia.org/wiki/They_Were_ElevenEach show will have a different pattern. All members will have double cast roles for East and West.
official site
http://gekijyo.net/Gekipro/stage/2016/03/11.html