Hello everyone 
You can achieve this process with the Duplicates and Uniques app. Basically, you can get the items that you want to copy in one group and then copy/move them over to the desired location. This will copy/move them over without the sub-items.
Here is a fairly comprehensive video that shows how the copy functionality works.
The video focus on the copy option but works the same for the move option too.
Additionally, the app can be used to address various needs apart from the one shown in the video. More about the app can be found here.
If you have any questions, you can always write to us at support@kolaai.com