Group cities only by the same offset and dst

[dorogoff]

Hi, thanks for the package, that's awesome that you did it! Have a small question, that's great that you group the cities by the same country code and offset, but any chance to group it only by the offset? Let's say Toronto and New York City will be in the same group? I thought I can reduce it by myself, but I see that there is no information about summer/winter time in results.

Thanks!