lastlogon

function Get-ADUserLastLogon($userName)
{
$dcs = Get-ADDomainController -Filter {Name -like "*"}
$time = 0
foreach($dc in $dcs)
{
$hostname = $dc.HostName
$user = Get-ADUser $userName -Server $hostname | Get-ADObject -Properties lastLogon
if($user.LastLogon -gt $time)
{
$time = $user.LastLogon
}
}
$dt = [DateTime]::FromFileTime($time)

Write-Host $username.samaccountname "last logged on at:" $dt 
}

$Groups = Get-ADGroup -Filter {Name -like "fi*"}

$groupmembers = @()
ForEach ($Group in $Groups) {
    $groupmembers += (Get-ADGroupMember -Identity "$($Group.Name)"  -Recursive)
}
$groupmembers = $groupmembers|select  -Unique

foreach($account in $groupmembers)
{

Get-ADUserLastLogon -UserName $account

}