I want to create a dimension, that groups the Values in the "Prop" Column and shows them. But when I click on "AA" I want to create a selection for the field "ID" with the values 1 & 2. How can I achieve this?
Not 100% sure on the question, but have you tried using filter panes yet? If you create two different filter panes, one for Prop and one for ID, after you select the Prop you want the IDs that are associated with that Prop will be in white in the filter pane, and the ones that aren't related to that Prop will be in grey.