Dimensions drawings in Layout

[WildcatFury]

For some reason I am struggling with a basic item. I have a Dimension Set drawing sent to the layout (construction) drawings. I want to add another dimension page for exterior dimensions only, so I set up another dimension set called "Dimension Set - Exterior" by copying the Dimension Set and renaming. When I send that drawing to the layout and I make a change to it, it changes the Dimension Set also. What am I doing wrong?