That's where you and most authors fail, you can have a group sex scene without needing every member to interact with every member. Two girls sharing a guy and being in a threesome, can have a threesome without needing to kiss each other/touch each other/ have sex with each other, they can focus on they guy they "love" that much that were ok to share. Same as two guys can have a threesome with a girl without needing to kiss each other/ have sex with each other and so, because not all the people in the world are bisex, and it isn't needed to have group sex, you can focus on someone. Saying that to have group sex scenes all the party involved need to interact with each other is kind of naive.
What you like/describe isn't an harem but polyamory and it isn't the same as harem, harem bunch of guys/girls that decide to share one guy/girl because they love him/her, if they love each other and the MC, it isn't the harem kink anymore, because you become one more of the relationships those girls have and not the focal point like in harem genre, so it fits more with polyamory. No matter what polyamory is not the same as harem, you may think it is, but it's not and if you like that fine, just pointing out it isn't the same fetish, harem doesn't mean the MC needs to share the girls with each other, while polyamory yes, people that like being "the king of the harem" but that don't like to share and or lesbian sex exist, because to be the focal point it's a part of that kink.
I'm just tired of games adversing "harems" where you can't decide anything that happens in it, where a girl suddently turn bisex or you watch how a LI of your "harem" is fucking other LI of your "harem" without you knowing it and instead of having a choice to not like it, the dev forces the MC to be ok with it, or "harem" games that later becomes a lesbfest because "lesbian sex is good, if you don't like it you are weird",or "would you want the girls there waiting for you instead of fuckign each others? even if the point of the harem is for them to share you as MC not each other...lol that's nonsense", or "I can't do a group sex scene if everyone involved in it isn't bisex because it's imposible for there to be people straight and if they are they become bi by porn logic", etc.
Whatever, sorry for the rant, I will just leave now, this game isn't for me and now I know it, thanks for answering.