#!/usr/bin/perl -w
use strict;
use warnings;
my %user = (
	1 => 'hallo|hallo|hallo|hallo|hallo',
	2 => 'hallo|hallo|hallo',
);
my %foo = (
	1 => 'hallo',
);
foreach my $user (
	grep {
		(split /\|/,$user{$_})[4] # das matcht auf garnichts
		#defined (split /\|/,$user{$_})[4] schmeisst Syntax und Implicit-Error
			&&
		defined $foo{(split /\|/,$user{$_})[4]}
	}
	keys %user
) {
	print "Treffer: $user\n";
}