Implicating threesome -> group_sex.

Reason: https://e621.net/wiki/show?nordirect=1&title=threesome says "three characters, ... engaging in mutual sexual activity."

group_sex wiki states

Images or animations depicting more than four characters engaging in sexual activities with each other simultaneously.

so not really.

Apologies, the existing implication of threesome -> group had me assuming the definition of group_sex.

Seems to be about 200 posts tagged with both threesome and group_sex.

Group_sex is implicated by gangbang.

Which is listed in the wiki as:

A group of three or more individuals all having sex with one other person, either sequentially or all at once. This is different from an orgy (where the individuals involved are engaged in sex among each other in various groupings) as well as from group sex (a group of people all having sex together through a chain of partners).

By the wiki definitions, gangbang requires at least four characters, while group_sex requires more than four. One of those should be fixed, I'm just not sure which.

It's an odd implication anyway, since the gangbang entry says that it's different from group sex.