Use this class to find groups within the Groups registry
Sample call
Group group = GroupFinder.findByName(grouperSession, "test", true);
Sample call to find groups a subject has specific privileges on
Set groups = new GroupFinder().assignPrivileges(AccessPrivilege.VIEW_PRIVILEGES) .assignField(Group.getDefaultList()).assignSubject(subject) .assignQueryOptions(new QueryOptions().paging(1000, 1, false)).findGroups();