how to fetch queue's related groups

Hi, All,

Could someone share the examples how to collect queue's related groups?

1. I've created the groups related to queue and define rights for these 
groups in the following way. It works. perl script.
....
foreach $key(keys %myHash) {
   my $myGroups = RT::Group->new(RT->SystemUser);
   $myGroups->_Create(Name => $key, Description => "Group for 
$QueueName", Domain => "UserDefined", Type => "", Instance => 0);
   foreach (@{$myHash{$key}}) {
     $myGroups->PrincipalObj->GrantRight(Right => $_, Object => $myQueue);
   }
}
...

2. But I can't find the examples how to select queue's related groups in 
another script.

........
my $Qs = RT::Queues->new($RT::SystemUser);
$Qs->FindAllRows;
$Qs->UnLimit;

  while ( my $Q = $Qs->Next ) {
   my $CurQ = $Q->Name;

   my $Groups = RT::Groups->new(RT->SystemUser);
   $Groups->LimitToUserDefinedGroups;
   ... ? how to limit to $CurQ ?
   while ( my $Group = $Groups->Next ) {
     my $CurGroupName = $Group->Name;
     print "$CurGroupName\n";
   }
}

Thanks a lot for your help.

Oleksandr