I mean I brute force one python execution state as repeated segment specific fetches to get the segment specific JSON which equates to users, new users, devices, and combine them into one datastructure which can be dumped as .CSV to feed cross-segment charting in excel.

I would make this happen inside python but I work with excel freaks, its kinder not to assume I know the charts they want.

  external_combined_datastruct={}

  for segment in ['GAXXXXXXX', 'GAYYYYYYYY', 'UAZZZZZZZ'] :
    with open_segment_connection_in_GA(segment) as this_seg:
      for i in get_segment_data(this_seg):
        data = jason.dumps(i.thedata)
        for j in data['some']['thing']:
             # add to the external combined datastruct

  # now.. print the external combined datastruct