A solution would be to allow merging BUT add a payware tag and prevent it from being uploaded to the DLS, as well as prevent it from being exported as a .cdp. If someone tries to export it, they'll get an error stating that the route has a payware route in it and that it cannot be exported. If it is somehow uploaded to the DLS, have something in the DLS software that detects the payware tag and prevents it from being uploaded. Cloning the route will preserve the payware tag even if you remove it in the config file.