That's the whole problem.
For example, when we divide it by 32, we get 32 public keys, which will be defined in 32 (predefined zones), including in our zone, where we expect it. One key per zone.
BUT which of the 32 zones the report starts with is not known. If you know at least one key in which zone is located, it is easy to calculate the remaining 31. Since they go "around the circle" in order. The starting point depends on the remainder of the division by 32, which we do not know.