Can you explain more the user experiece you are seeking?
If the user selets Dim 1 = Baby Product, then by association the selection of Dim2 = Milk Bottle works as expected.
Likewise if the user drills down using your "Test Table" and the drill down group.
If the user instead starts with clear selections, and selects Dim2 = Milk Bottle, then they can either select a Dim 1 value, or a Dim3 value, but the association takes care of itself. You could add a button that selects one or the other in Dim 1 if you want (where Action is 'Select in Field', Field is 'Dim 1', and value is Baby Product, for example). But if you already have a list box with Dim 1 available, would it not be easier to just use that (and more clear to the user)?