Sometimes, even though there are more than two things, the kind of comparison suggested by the context requires taking them two at a time, and between is fine in those cases. The author of the first sentence was probably thinking in terms of A talks to B, B talks to A, A talks to C, C talks to A, B talks to D, D talks to B, and so on. The author of the second sentence was probably thinking in terms of comparing the heights of A and B, then of A and C, then of A and D, then of B and C, and so on.
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