Unfortunately, this is currently not possible via the API services. However, you can extract the ProductGroup information for all active products using the
Product Partition Report and then subtract that list from the list of all product groups/partitions created by you, assuming that information is available with you locally. Alternatively, you can try setting the
includeZeroImpressions header in your report to true and check if you are able to see the information for all product partitions in the report.