Identify Japanese novel with sister helping seduce teacher and her sister / headmistress and daughter

[zombie]

Basically as the title says ,It was a game with a Japanese title I think where you could have sex with a teacher and her sister from another school and the headmistress of your school and her daughter, I think your sister used to help and there were multiple endings including rape.

 

[zarax]

Basically as the title says ,It was a game with a Japanese title I think where you could have sex with a teacher and her sister from another school and the headmistress of your school and her daughter, I think your sister used to help and there were multiple endings including rape.

Shot in the dark but I thinks it's Sansha Mendan

 

[zombie]

Shot in the dark but I thinks it's Sansha Mendan

Actually is, cant believe you got it off that description.
Thanks, Much appreciated.