You can create a "library" of QoS policies that can be re-used by different DCPS domain elements.
From the main diagram a Policy Library can be created by either double-clicking on the PolicyLib tool in the palette, or by clicking on the PolicyLib tool and then dragging the region on the diagram surface that the policy library figure should occupy. After that specify the name to use for the library.
The library can then be opened by double-clicking on the library. A new diagram editor will be opened (using the same diagram file used for the main diagram).