Jin doesn't even like 'Sendou' that way. He reacted when Anri seduced him but did not react when Sendou tried to seduce him again EVEN after he liked mansex.
He was also attracted to Anri's looks at the start and then his personality. I don't see Jin liking Sendou ever. Not once did it show that Jin was attracted to him. And the last part of the manga showed that Sendou wasn't even his type. He did not even care when Sendou saw him having sex with Anri. To him Sendou is only a good friend, you shouldn't twist his friendship for Sendou for something else JUST because Sendou likes him. Just because someone likes you, you're not entitled to like them back. And in this case Jin doesn't. You should let that dream go.
NEED ANOTHER DOUJIN AND KEEP AWAY CHILDISH SEME...