gistfile1.txt

$DateTime = Get-Date -f "yyyy-MM" 
$CSVFile = "C:\AD_Groups"+$DateTime+".csv" 
$CSVOutput = @() 
 
$ADGroups = Get-ADGroup -Filter * 

$i=0 
$tot = $ADGroups.count 
 
foreach ($ADGroup in $ADGroups) { 
    $i++ 
    $status = "{0:N0}" -f ($i / $tot * 100) 
    Write-Progress -Activity "Exporting AD Groups" -status "Processing Group $i of $tot : $status% Completed" -PercentComplete ($i / $tot * 100) 
    $Members = "" 
 
    $MembersArr = Get-ADGroup -filter {Name -eq $ADGroup.Name} | Get-ADGroupMember | select Name, objectClass, distinguishedName 
    if ($MembersArr) {  
        foreach ($Member in $MembersArr) {  
            if ($Member.objectClass -eq "user") { 
                $MemDN = $Member.distinguishedName 
                $UserObj = Get-ADUser -filter {DistinguishedName -eq $MemDN} 
                if ($UserObj.Enabled -eq $False) { 
                    continue 
                } 
            } 
            $Members = $Members + "," + $Member.Name  
        } 
        if ($Members) { 
            $Members = $Members.Substring(1,($Members.Length) -1) 
        } 
    } 
 
    $HashTab = $NULL 
    $HashTab = [ordered]@{ 
        "Name" = $ADGroup.Name 
        "Category" = $ADGroup.GroupCategory 
        "Scope" = $ADGroup.GroupScope 
        "Members" = $Members 
    } 
 
    $CSVOutput += New-Object PSObject -Property $HashTab 
} 

$CSVOutput | Sort-Object Name | Export-Csv $CSVFile -NoTypeInformation 

I changed line 5 to limit the amount of groups to just those in a specific OU using -SearchBase "OU=Distribution Groups,DC=tor,DC=rapid7,DC=com"
Then added a where cmdlet to line 16 to feed the output of Get-ADGroupMember into.
"| where {$_.objectclass -eq "group"}"
Worked a charm