What are we calling a "threesome"/"foursome"? Full-on penetration with at least one participant and physical contact with another? Or just physical contact (touching) with more than two people?
Of the threesomes listed, my first guess would be C (Sophia/Ellie/Julia). My PREFERRED choice would maybe be E (Sophia/Aiden/Andre), followed by H (Dylan/Sophia/Patricia), A (Sophia/Ellie/Dylan), and F (the Elders),in that general order.
Of the foursomes listed, my first guess would be L (Sophia/Liam/Andy/Cathy). M (museum) if we're just talking about some kissing and/or groping, not full-on penetration. My PREFERRED choice would be K (Sophia/Sam/Amber/Dylan), but only likely if there is some semi-secret pairing off for groping in the pool or something.
Rambling thoughts: For threesomes, I would guess the seniors early on, if dual handjobs counts. Technically, two of the Apostles got dual handjobs. But although I loved the images in that event, the touching was very clinical IMHO. Sophia expressed no sexual connection at all, and The Apostles didn't really know what they were doing.
Of those not listed, I'd like to see Dylan/Claire/Marie get into something. (Mostly I'd just like to see Dylan and Claire getting a little physical in the barber chair).
If we're just talking some touching in the same room, maybe Christine/Ellie/Dylan is a near possibility, and of course Aiden/Andre/Jen. I'd like to see Sophia/Ellie/Patricia. Yes, Sophia and all of The Apostles. Sophia/Tyler/Logan/Ellie I could see something happening but not full-on sex.
Dylan/Patricia/Claire/Sophia/Amber in various combinations. I think that Dylan/Sophia would be very late, but a boy should lose his virginity to his mother. But I'd like to see Dylan get some foreplay action with Patricia, Amber, Ellie and Claire individually before that. But now I'm getting off track.