Hi, you can crete an additionalfield on script with just those values, in the same table where dim1 is loaded you can add:
If(Match(Dim1Field,'Value1','Value2',...), Dim1Field) as Dim2Field
If you want selctions in only the Dim1field you can use a calulated dimension like: Aggr(If(Match(Dim1Field,'Value1','Value2',...), Dim1Field), Dim1Field)