Regarding merging files from Several Projects

Dear All, We have a requirement in our QUARTUS II 9.0 kindly give your feedback.We have around 20 project folders. We have tested them separately in the past, when we arrived at our final project we have used all the folders as libraries in the final project. Now we wish not to add them as separate projects (due to excessive no of files and cumulative size of the folder) and want to have all the blocks and components in the same folder !! Is there a method to do this ? If we have to manually copy paste some files from each project into a common folder (where we shall have to final project) then what all files we must copy ?