When Shiori finds out you are also dating with Nanami (I don't know if this occurs to other characters), sometimes Shiori will say that she don't want you to date with Shiori anymore. The choices after that is only "Stop dating Shiori" and "Stop dating both of them".
I like to imagine dating a half of Shiori and then the other half get jealous lol
Any ETA for v9? I would really like the afterstories, especially for Kiyomi and Nanami.