That's really interesting, thanks very much. I've proved to myself it works by using the following:

while (@online) {  
  push (@{$links[$_]}, shift @online) for 0..2;
}

@links1 = @{ $links[0] };
@links2 = @{ $links[1] };
@links3 = @{ $links[2] };

print "@links1<br>@links2<br>@links3";
[download]

I shall try to work with the anonymous arrays going forward rather than the named ones but it does all start to get rather obscure and difficult for a simpleton such as me...