Use the "Reuse" function for this. You will still have to clean up the silk, because for some reason, reuse doesn't include the designator placements. But this will work.
Select the circuit you want to duplicate, and save it as a reuse, then select the duplicated parts that have been imported from your schematic and click on the "Make Like Reuse" button under routing, then select the appropriate saved reuse.
Understand that the two circuits or circuit sections have to be EXACTLY the same, down to connectivity and part names (but not designators of course).