use strict;
use vars '$sortstr';
my @list = qw(a z b y c x); 
my @list2 = qw(zulu zuzu zucu charlie fred xray yankee bravo alpha); 

$sortstr = join('', @list);
my @sorted_list =  sort mycmp @list2; 

sub mycmp {
    my ($A, $B)= @_ ? @_ : ($a,$b);
    my $temp;
    my $Aspot = ($temp = index($sortstr,substr($A,0,1))) < 0 ? 
	length($sortstr) : $temp;
    my $Bspot = ($temp = index($sortstr,substr($B,0,1))) < 0 ? 
	length($sortstr) : $temp;
    
    return 
	$Aspot <=> $Bspot
	    ||
		mycmp(substr($A,1),substr($B,1))
	    ||
		$A cmp $B
}