Build 4.9.0.34 of xlsgen adds feature improvement to pivot table row grouping.

Before this build, only data interval was made available from the GroupBy interface.

Now MinimalValue and MaximumValue can be manually set.

And here is an example of this (C++) :

xlsgen::IXlsPivotTablePtr pt = worksheet->NewPivotTable();
pt->DataSource->Range = L"Sheet1!D4:F14";

xlsgen::IXlsPivotTableFieldPtr pf1 = pt->Rows->AddByName(L"s2");
pf1->AggregateFunction = xlsgen::aggrpivotfunction_none;
pf1->SortAscending = TRUE;

xlsgen::IXlsPivotTableFieldGroupByPtr pf1g = pf1->GroupBy;
pf1g->Interval = 2;
pf1g->MaximumValue = 40;

xlsgen::IXlsPivotTableFieldPtr pf_d1 = pt->Data->AddByName(L"s3");

pt->Options->Layout = xlsgen::pivottablelayout_tabular;
pt->Options->BuiltInPivotTableStyle = xlsgen::pivottablestyle_medium14;
pt->Options->ShowRowStripes = TRUE;

pt->InsertAt(1,1);