Looking for name of old Hentai anime

[narutousumaky]

I'm trying to find a old hentai I watched ages ago

A guy gets help from another girl to blackmail the 3 student council members after they cause his "Sister?" to get raped

The first girl he blackmails he does so by finding her making out with a teacher

This is all I really remember, but it's been bugging me that I can't find it

 

[bakaest]

ヤバい！−復讐・闇サイト−　
湯川　文乃×印南　美涼×椿　利奈 妹殺しの犯人は誰だ？　編
made by 鈴木みら乃