retrieve rows with highest values in from array

John_Dodo 

I don't actually understand the data relationship between table 1 and 2 - specifically, I don't know where "family1", "family2", etc. are coming from in table 2, col2.

For the sake of providing an example, I'm going to assume that table 1, col3 ("son1", "son2", etc.) equates to "family1", "family2", etc in table 2, col2.

If that's not the case, then you'll need to better-explain how to get from table 1 to table 2.

If it is the case, then I've used the following example along with your data from table 1 to produce the output below the script.

Script

$Hashcode = 0;
$NewHashCode;
$LastSon = "";
$Index = 0;

Import-Csv -Path D:\Data\Temp\Forum\forums.txt -Delimiter ";" |
    Sort-Object -Property col3, col2, @{ e = "col4"; d = $true} |
        ForEach-Object {
            if ($HashCode -ne ($NewHashCode = [string]::Concat($_.col3, $_.col2).GetHashCode()))
            {
                $HashCode = $NewHashCode;

                if ($LastSon -ne $_.col3)
                {
                    $LastSon = $_.col3;
                    $Index++;
                }

                [PSCustomObject] @{
                    col2 = "family$Index";
                    col3 = $_.col2;
                    col4 = $_.col4;
                }
            }
        }

Sample output

Cheers,

Lain