How to loop through mulitple azure subscriptions parallelly - azure

Question

I am trying with nested ForEach-Object -Parallel to loop through multiple azure subscriptions parallelly and get data from all VMs in one go. I am using below code:
$SubsJob = Get-AzSubscription -WarningAction SilentlyContinue | Where-Object {$_.Name -match 'abc'} | ForEach-Object -Parallel {
$Context = Set-AzContext -Tenant $_.TenantId -SubscriptionId $_.SubscriptionId
[System.String]$ScriptBlock = {Get-Process}
$VMsJob = Get-AzVM | ForEach-Object -Parallel {
$FileName = $using:Context.Subscription.Name + "_$($_.Name)_" + (Get-Random) + ".ps1"
Out-File -FilePath $FileName -InputObject $using:ScriptBlock -NoNewline
$Output = Invoke-AzVMRunCommand -Name $_.Name -ResourceGroupName $_.ResourceGroupName -CommandId 'RunPowerShellScript' -ScriptPath $FileName
$PSCustomObject = [PSCustomObject]#{Subscription = $using:Context.Subscription.Name; ServerName = $_.Name; Output = $Output}
#Remove-Item -Path $FileName -Force -ErrorAction SilentlyContinue
Write-Output $PSCustomObject
} -ThrottleLimit 200 -AsJob
Write-Output $VMsJob
} -ThrottleLimit 200 -AsJob
I am not able to get it work, not sure what is wrong. One thing I observed while debugging is that, Get-AzVM command is getting VMs list from all the subscriptions rather than specific subscription. I came to know that by looking at the Out-File -FilePath $FileName which are generated.
sub1_server1_980337551.ps1
sub2_server1_42701325.ps1
server1 is only present in sub1 but it is being picked in sub2 as well.