A System group can be removed from the site via the
Remove group
option. When a system group is removed from a site, then every member of that group will be removed from the site, subject to the following limitations; If (a) a user was added to the site before being added to the site as part of that system group, or (b) the user was added to the site in a separate system group, then that user will retain their site membership, either through their individual site membership or through their membership in the other system group.