Is "Divide the pizza between the three friends" correct?

Why

Neha's mistake is a reasonable one to make, since both words genuinely mean something like "shared or located within a group", and it's easy to assume they're simply interchangeable. English traditionally reserves "between" for exactly TWO people or things — "between you and me", "choose between two paths" — while "among" is used for THREE or more, where the group is thought of together rather than as distinct pairs. With three friends sharing a pizza, the sharing genuinely involves a group of three, which is exactly the situation "among" is built to describe. Test: "the secret is between us two" sounds right for two people, but "the secret is between the five of us" sounds noticeably less natural than "the secret is among the five of us" — that discomfort is the two/three-plus distinction being felt directly. Her brother is right: "among" is the traditional word for three or more, while "between" is reserved for exactly two.