#!/usr/bin/perl

use strict;
use warnings;

# start with an array of arrays (list of lists, which can come from a data file):
# each row contains all the "synonymous" names in a set, and
# each element in the row becomes a hash key whose value is
#    a reference to the whole row/set of synonymous names:

my %altnames;  # will be a HoA

while (<DATA>) {
    my @nameset = split;
    for my $name ( @nameset ) {
        if ( ! exists( $altnames{$name} )) {
            $altnames{$name} = \@nameset;
        }
        else {
            my $newname = $name;
            $newname .= " " while ( exists( $altnames{$newname} ));
            $altnames{$newname} = \@nameset;
        }
    }
}

for my $name ( qw/Allen Bill Chuck Dave Edward Jan/ ) {
    my $modifier = '';
    for ( grep /^$name\s*$/, keys %altnames ) {
        print "The name $_ is $modifier a member of the set @{$altnames{$_}}\n";
        $modifier = 'also';
    }
}

__DATA__
Allen Al
Charles Chuck Chas
David Dave
Edward Eddie Ed
Janet Jan
Janice Jan
William Will Willie Bill Billie