Instead of waiting for a specific entry in the folder to change, you could run the "Wait for Entry Change" activity on the Folder itself, and then use the Folder Contains conditions to wait until any of the entries meets a specific requirement. Once that requirement is met, you can then use the Find Entries activity to get all of the entries in that folder and move them each to the destination.

Depending on the process it might also be easier to put all related documents in their own folder within a container and move the whole folder.