bool allHoleNumbersEqual(const vector<BamRecord>& group) 
{
    if (group.empty()) 
        return true;
    const auto firstHoleNumber = group[0].HoleNumber();
    for (size_t i = 1; i < group.size(); ++i) {
       if (group[i].HoleNumber() != firstHoleNumber)
           return false;
    }
    return true;
}

vector<int32_t> whitelist = { 50, 100 };
ZmwGroupQuery query(whitelist, dataset);
for(const vector<BamRecord>& group : query) {

    assert(allHoleNumbersEqual(group));

    for (const BamRecord& record : group) {
        assert(record.HoleNumber() == 50 ||
               record.HoleNumber() == 100);
    }
}