10 Things I hate About You based Gachiakuta Au (because it's one of my favourite movies and I do what I want) where in an attempt to prevent Zanka from getting together with Jabber/Follo/Fu/whoever you ship him with, his parents tell him he isn't allowed to date until one or both of his older siblings are in a relationship.
His unsocial, workaholic, blunt, stubborn as a mule's backside older siblings.
Never one to back down from a challenge no matter how unlikely it is for him to succeed Zanka enlists his soon to be partner and the rest of his friends to try and set the older Nijiku up with anyone and they end up hiring fake partners for them.
Kyouka with either Cthoni or Semiu and Goka with Enjin.
Obviously the fake partners and the older Nijikus eventually form proper feelings for eachother and Zanka gets to date his chosen partner. Maybe the experience actually causes the Nijiku siblings to grow closer and bond more as a result.
(You guys can choose how much angst is involved regarding the reveal of Kyouka/Goka's partners originally only being hired to date them for Zanka's benefit.)