use strict;
my %names;

while (<>) {
 my ($label, $name1, $name2, $name3, $name4) = split /:/;
 $names{$label}{$name1} = $name2;
 $names{$label}{$name3} = $name4;
} 

##</code><code>##

# Untested, because I rarely use symbolic refs :)
while (<>) {
 my ($label, $name1, $name2, $name3, $name4) = split /:/;
 $$label{$name1} = $name2;
 $$label{name3} = $name4;
}