How to make a set of values read in from a config file, globally available to set of scripts

Hi

Recently I wanted to ensure a set of related  scripts were able to access a set of values read in from a config file. My current method although works, does not seem reliable leading to my calling scripts bombing out with errors as $domain and others are empty.

In my getConfig file

# what script am I running
Write-Host $MyInvocation.MyCommand.Path
#... and the directory
$directorypath = Split-Path $MyInvocation.MyCommand.Path
# read the config file which is in the directory
$configfile = $directorypath + '\config.xml'


#read configuration file config.xml into variable $xmlfile
$xmlfile = [xml](get-content "$configFile")


# Determine the properties defined by xml elements we want to use cgoing forward 
$domain = $xmlfile.Configuration.Domain.Name
Write-Host -fore Blue "Domain:         $domain"

In each of my calling scripts I have

$scriptRoot = Split-Path $MyInvocation.MyCommand.Path
Write-Host $scriptRoot



# read the config file which is in the same directory obtain the variables we need for the functions below
& "$scriptRoot\Get-SP2013Config.ps1"  
# another attempt but this time with a module equally unreliable. 
# Import-Module "$scriptRoot\Get-SP2013Config.psm1"  -Global -Force 

Write-Host -ForegroundColor DarkGreen $domain

What I am seeing is the called script runs every time and  displays the values I expect thereafter the values are lost and not in the scope of the calling script. I can fix the situation by running the called script before I invoke the calling script ( which subsequently calls the called script again) , thereafter my $domain etc are  populated. What I want is a bomb proof method .