my %EMail = ( # This hash best accessed via GetEMailFor()
    Category1 => { "Name One",   'some1@address.com', },
    Category2 => { "Name Two",   'some2@address.com', 
                   "Name Three", 'some3@address.com', },
    Category3 => { "Name Four",  'some4@address.com',
                   "Name Five",  'some5@address.com', 
                   "Name Six",   'some6@address.com',
                   "Name Seven", 'some7@address.com', 
                   "Name Eight", 'some8@address.com', },
# And so on...
);

# GetEMailFor( $key, [$key2, $key3...] )
#
#   Returns the requested e-mail address.
#   If more then one address is found, they are returned as
#   a comma delimeted scalar.
#   The $key may be the person's category or name.
#
sub GetEMailFor
{
    my @addresses = ();
    while( @_ )
    {
        my $request = shift;
        for( keys %EMail )
        {
            if( $_ eq $request )
            {
                push @addresses, values %{$EMail{$_}};
                next;
            }

            for my $name ( keys %{$EMail{$_}} )
            {
                if( $name eq $request )
                {
                    push @addresses, ${$EMail{$_}}{$name};
                    next;
                }
            }
        }
    }
    return join ',', reverse @addresses if $#addresses;
    return $addresses[0];
}

# So

print GetEMailFor( 'Category2' );
# prints: some2@address.com,some3@address.com

print GetEMailFor( 'Name Five' );
# prints: some5@address.com

print GetEMailFor( 'Category1', 'Name Seven' )
# prints: some1@address.com,some7@address.com