
Market resolves YES if a verified instance like a pornographic film is released, or a space organization verifies the occurrence.
https://en.wikipedia.org/wiki/Sex_in_space

Any specific graph-connectedness or population requirements for the participants?
(Also, if it isn't dedicated to Dionysus, it isn't an orgy, it's just sparkling group sex.)
@Stralor 's ruling is
It's 5+ for an orgy, with multiple people engaging with multiple people, in the same space. Contrast to:
a threesome, where there are only 3 (duh)
a train, where there's one person who has many other partners in sequence
a gangbang, where there's one person who has many other partners at once
a (full-)swap, where two or more couples have sex with a partner from another couple, aka swinging