Custom "sort" routine

slatibart has asked for the wisdom of the Perl Monks concerning the following question:

Hi, i have a list of top level domains which also have sub tlds. Normal sort produces me a list like that

.com.fj
.com.sb
.com.nf
.com.co
.com.mv
.coop
[download]

but this would be the appreciated sorting

.com.co
.com.fj
.com.sb
.com.mv
.com.nf
.com.sb
.coop
[download]

First, the toplevel, then the sub tld. My ideas was to start with this code :

  @list= sort { my ($sub1,$tld1)=split /\./,$a; my ($sub2,$tld2)= spli
+t /\./,$b;  $tld1  cmp $tld2  } @list;
[download]

But didn't worked as expected. Where is my code wrong ? Thanks