Group Method (Range Object) Example
This example groups the field named "ORDER_DATE" by 10-day periods.
Set pvtTable = Worksheets("Sheet1").Range("A3").PivotTable
Set groupRange = pvtTable.PivotFields("ORDER_DATE").DataRange
groupRange.Cells(1).Group by:=10, _
periods:=Array(False, False, False, _
True, False, False, False)