Was thinking more of 3.5 setting
The closest I can think of is this fun little 3.5 feat. I don't remember its name or book, sadly, but someone will probably remember it.
How it works is very simple: A creature size Small or lower who has this feat can share a 5' square with any number of other Small or lower creatures who also have this feat. So it's perfectly possible to have, say, three Halflings share the same 5' square with two of them dual-wielding and the third buffing/coordinating them so that he's effectively "wielding" them.
Your DM should allow it as long as you keep the number small. There have been players who broke the game by having a hundred gnomes occupy a 5' space together and act like a giant wrecking ball.