I am fairly new to PowerShell and just trying to get plug some gaps with my main support role using PowerShell, so far its been great however I am currently stuck on trying to find a solution for the following.

Here is a sample of the input data:

Group Name User ID
GROUP1 X9998988
GROUP1 X9982293
GROUP1 X9953089
GROUP1 X9952998
GROUP1 X9209289
GROUP1 X9205093
GROUP1 X9208889
GROUP1 X9292353
GROUP1 X9293330
GROUP1 X9229034
GROUP1 X9222338
GROUP2 X9205298
GROUP3 X9953800
GROUP3 X9933359
GROUP3 X9993288

Here is an example of how I would like that data to look:

Group Name User ID
GROUP1 X9998988,X9982293,X9953089,X9952998,X9209289,X9205093,X9208889,X9292353,X9293330
GROUP2 X9205298
GROUP3 X9953800,X9933359,X9993288

This is the code I have created so far, hopefully I am on the right track:

  $csv_file = Import-Csv "C:TestOther_Managers.csv" | 
    Group-Object "Group Name" | Foreach-Object { 
                  $groups = $_.Group."Group Name";
                  $users = $_.Group."User ID";

  }
 
 
 foreach ($row In $groups){

 $output = $row  | Select    @{Name="Group";Expression={$groups}},
                             @{Name='Users';Expression={($users-join ',')}};


$output | Export-Csv -Path "C:TestOther_Managers_out.csv" -NoTypeInformation


}

The Result:
Group Users
GROUP3 GROUP3 GROUP3 X9953800,X9933359,X9993288