The shunt utilites: shunt, exactly, and flyisofs,  were originally
written for burning multi-set CDROM backups using mkiosfs and cdrecord.

The port maintainer uses shunt with flyisofs to make offsite copies of
compressed backups onto a series of DVD+RW disc:

        shunt -c 'dump -0af - /path/to/backups' +
           'flyisofs mbc=2295104 fbc=2000000 | growisofs -Z
           /dev/rcd0c=/dev/fd/0'

"$ <utility> -h" provides minimal usage information.  
For detailed information, see http://www.serice.net/shunt/
