Windows PowerShell Script Help

I found a Fourm that had a post on it by Richard Mueller that had a script he posted to help setup automation of adding users to a group with a PowerShell Script. The script works great, but I want to add more $OU's to it but when you do that, it only pulls the users from the last OU. I am wondering what commands I need in order to add more OU's?

Here is the script that Richard posted:

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A PowerShell script that ensures that all users in a specified OU are members of a specified group. This also ensures that there are no other members.

# PowerShell script to ensure that all users in a specified OU
# are members of a specified group. Also ensure that there are
# no members of the group that are not user objects in the OU.

# Specify the OU.
$OU = [ADSI]"LDAP://ou=West,dc=MyDomain,dc=com"
# Specify the group.
$Group = [ADSI]"LDAP://cn=MyGroup,ou=West,dc=MyDomain,dc=com"

# Hash table of users in the OU.
$List = @{}

# Enumerate all objects in the OU.
$arrChildren = $OU.Get_Children()
ForEach ($Child In $arrChildren)
{
  # Only consider user objects.
  If ($Child.Class -eq "user")
  {
    # Add all users in the OU to the hash table.
    $List.Add($Child.distinguishedName, $True)
    # Check if user a member of the group.
    If ($Group.IsMember($Child.ADsPath) -eq $False)
    {
      # Add the user to the group.
      $Group.Add($Child.ADsPath)"Added " + $Child.distinguishedName
    }
  }
}

# Enumerate all members of the group.
ForEach ($Member in $Group.member)
{
  # Check if this member object is a user object in the OU.
  If ($List.ContainsKey($Member)-eq $False)
  {
    # Remove this member from the group.
    $Group.Remove("LDAP://$Member")"Removed " + $Member
  }
}