Hi,
You need to use query designer and in filter pane drag the characterstic over which you need to add the restriction.
--After this right click over it and click on restrict.
--From the drop down select characterstic restriction and click on new button.
From the details tab you can decide which kind of values to absorb like single server etc.
Then select the restriction and save it.
Hope it helps 
Regards,
Pranay Sharma