$TargetCluster = "Cluster-Name"
$TargetGroup = "VM-Group-Name"

$VcSv = "vcenter.vsphere.local"
$VcUser = "administrator@vsphere.local"
$VcPass = "password"

Import-Module VMware.PowerCLI

Connect-VIServer -Server $VcSv -User $VcUser -Password $VcPass
$PowerOnVms = Get-VM | Where-Object { $_.PowerState -eq "PoweredOn" }
Foreach ($TargetVm in $PowerOnVms) {
    if ($TargetVm.GuestID -match "windows.*") {
        Get-Cluster -Name $TargetCluster | Get-DrsClusterGroup -Name $TargetGroup | Set-DrsClusterGroup -VM $TargetVm -Add
    }
}

Disconnect-VIServer -Server $VcSv -Confirm:$False