How to: Add or Delete an Attribute Relationship
You can create an attribute relationship between any two attributes in a dimension. Most often, you add an attribute relationship to denote a natural hierarchy relationship in a user-defined hierarchy.
In Dimension Designer, open the dimension that contains the source attribute.
Set the Attributes pane of Dimension Designer to tree view. For more information, see How to: View Attributes in a Tree, List or Grid in Dimension Designer.
Drag the source attribute that you want to relate to a target attribute onto the <new attribute relationship> field under the target attribute.