According to the provided information, it is not clear enough the exact condition that you apply to the filter. However, note that the SetCondition offers a public Items collection:
PropertyGroupDescriptionBase description = (PropertyGroupDescriptionBase)this.radPivotGrid1.RowGroupDescriptions;
LabelGroupFilter filter = new LabelGroupFilter();
SetCondition condition = new SetCondition();
condition.Comparison = SetComparison.Includes;
filter.Condition = condition;
description.GroupFilter = filter;
I have attached my sample project for your reference. Please give it a try and see how it works for your case.
Should you have further questions please let me know.
Dess | Tech Support Engineer, Sr.
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