#!/usr/bin/perl

use strict;
use warnings;

my $groupname = "derp";

my %replaceGroups = (
    "Group.test" => "Group.$groupname",
    "Group.eso"  => "Group.$groupname",
);

my $regex = join "|", keys %replaceGroups;
$regex = qr/$regex/;

# both cnstrings for testing.
my $cnstring = "CN=ext.Group.eso,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local";
#my $cnstring = "CN=ext.Group.test,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local";

$cnstring =~ s/($regex)/$replaceGroups{$1}/g;

print "$cnstring\n";

##</code><code>##

CN=ext.Group.derp,OU=External,OU=ExDistriGroups,OU=Accounts,DC=eso,DC=local