my $groupid = ...;
my $newvalue = ...;
foreach my $key (@somekeys) {
  my ($obj) = MyCDBI::Obj->search(groupid => $groupid, userid => $key);
  if (defined $obj) {
    if ($newvalue eq 'somevalue') {
      $obj->status(lc $newvalue);
    } elsif ($newvalue eq 'someothervalue') {
      $obj->status("something");
    } elsif ...
      ...
    }
    print "new value: ", $obj->status;
    $obj->update;
  } else {
    print "Not found";
  }
}