A field I use for columns in a pivot table has a large number of items. Only a handful of these items are significant. The rest I group into Others. This I know how to do. The issue I'm trying to solve is that every few weeks a new item is added to the data. So when this happens I have to redefine the formula (Others := item1+item2+item3+item3+...+itemN). Hoever, the set of significant items never changes.
Is there a way I can calculate Others as <FIELD_TOTAL> - (itemA + itemB + itemC+itemD)
?