The entire group can be granted access to the appropriate directory.
These add-ons can be downloaded, updated and removed using an in-game add-on server; alternatively, they can be installed and updated by manually downloading the add-on's files and placing them in the appropriate directory, or they can be removed by deleting these files.
Links in the dataset description boxes will either download the data file desired, or take you to the appropriate directory on the ftp server, where you can make selections based on date.
Adding these into a game simply required the files to be placed in the appropriate directories in the user's file system.