Kidou Senshi Gundam 00 ~Onna no Sensou Konzetsu Keikaku~

A certain organization attempts to brings an end to all wars by means of military intervention.
In the midst of this conflict, a young princess seeks the help of other nations to save her country, which suffers from the depletion of its oil supplies.
She wishes to save her country without fighting. For this she is willing to even sacrifice her own body... That is the extent of her determination.

However, her noble intentions are abused by a group of men, who turn the poor princess into their plaything. For her as well as for a number of other young women, the curtain rises on a life of sexual insult.

[From DLsite English]