Download/create a set of files associated with each subset
Example: https://github.com/jsta/gssurgo_data/blob/master/Makefile
Create a file holding a list of subset ids
Example: https://github.com/jsta/nesR/blob/master/477/Makefile
Brute force write out a list of files for each subset
Example: https://github.com/jsta/realsat-r/blob/master/Makefile