Hi Vaishali,
Try using below as grouped dimension and for corresponding measure.Suggest you to do this at universe layer, as it would be much more simpler with just one case statement and measure gets split accordingly.
groupedDim=IF([Product]="A";"A";IF([Product]="B";"B";"B";IF([Product]="C";"C";IF(([Product]="D" AND [Product]="E" AND [Product]="F"));"DEF";IF(([Product]="A" AND [Product]="B" AND [Product]="C");"ABC";IF(([Product]="A" AND [Product]="B" AND [Product]="C";[Product]="D" AND [Product]="E" AND [Product]="F");"XYZ"))))))
Measure=IF([Product]="A";[Measure] Where([Product]="A");IF([Product]="B";"B";[Measure] Where([Product]="B");IF([Product]="C";[Measure] Where([Product]="C");IF(([Product]="D" AND [Product]="E" AND [Product]="F"));([Measure] Where([Product]="D")+[Measure] Where([Product]="E")+[Measure] Where([Product]="F"));IF(([Product]="A" AND [Product]="B" AND [Product]="C");([Measure] Where([Product]="A")+[Measure] Where([Product]="B")+[Measure] Where([Product]="C"));IF(([Product]="A" AND [Product]="B" AND [Product]="C";[Product]="D" AND [Product]="E" AND [Product]="F");([Measure] Where([Product]="A")+[Measure] Where([Product]="B")+[Measure] Where([Product]="C")+[Measure] Where([Product]="D")+[Measure] Where([Product]="E")+[Measure] Where([Product]="F"))/6))))))
Thanks
Mallik