Not sure I completely understand what you need to accomplish, if you have 4 licenses you can register to 4 devices. Once you have the program installed and registered in each device you can open the main device that has all your information or if you have no information at all yet then choose the one you will use as the main device for the other 3 to connect to and download the data from. Once you have chosen the PC you will use as the main one you can go to ¨Options¨ > ¨Sync Device¨ here you will have the option to sync the main device to Dropbox (You will need a Dropbox Account), once you sync the main device you can go to the other devices and do the same to sync them. This should allow you to see the same information on all 4 devices.
You can confirm with NCH tech team here: https://www.nch.com.au/support/index.html