Deleting originals from cloud, but leaving smart previews

I was wandering if its possible to delete the originals from the cloud (as they are saved locally) but leave the smart previews only. 

I am using mainly lightroom classic, but from time to time import some raw files to my mobile devices and import them to lightroom cc, then they get downloaded to lightroom classic in the sync folder and I dont need the high res files in the cloud, but want to be able to access the smart previews. In order to do that I have to delete them from lighroom cc and then reupload them using lightroom classic collections. 

Is there another/easier way to do this. 

Best wishes!