function Get-CASActiveUsers {

  [CmdletBinding()]

    param(

    [Parameter(Position=0, ParameterSetName="Value", Mandatory=$true)]

    [String[]]$ComputerName,

    [Parameter(Position=0, ParameterSetName="Pipeline", ValueFromPipelineByPropertyName=$true, Mandatory=$true)]

    [String]$Name

  )

 

  process {

    switch($PsCmdlet.ParameterSetName) {

      "Value" {$servers = $ComputerName}

      "Pipeline" {$servers = $Name}

    }

    $servers | %{

      $RPC = Get-Counter "\MSExchange RpcClientAccess\User Count" -ComputerName $_

      $OWA = Get-Counter "\MSExchange OWA\Current Unique Users" -ComputerName $_

      New-Object PSObject -Property @{

        Server = $_

        "RPC Client Access" = $RPC.CounterSamples[0].CookedValue

        "Outlook Web App" = $OWA.CounterSamples[0].CookedValue

      }

    }

  }

}