Powershell workflow/parallel citrix sessions - powershell

Question

Edit - I should preface this by saying I'm very new to powershell. This is one of the first "complicated" scripts i've tried to write.
I'm trying to use workflow/parallel to run a script against two lists simultaneously. after I get it working, the goal will be to add multiple lists, to cut down on the time it takes to process each one.
The script by itself works great. Adding the workflow returns nothing. :/
$Global:ctxsession = Read-Host -Prompt 'Input the Username'
$serverlist1 = get-content .\serverlist1.txt
$serverlist2 = get-content .\serverlist2.txt
function citrixlist {
#([string]$Servers)
Param(
[Parameter(Mandatory=$True,Position=1)]
[string]$servers
)
foreach ($server in $servers) {
#ping first
if (Test-Connection -count 1 -computer $server -quiet) {
#temporary write-host to see where it hangs (might leave in permanently)
Write-Host $server
#check for sessions
$sessions = qwinsta /server $server| ?{ $_ -notmatch '^ SESSIONNAME' } | %{
#separating into objects
$item = "" | Select "Active", "SessionName", "Username", "Id", "State", "Type", "Device"
$item.Active = $_.Substring(0,1) -match '>'
$item.SessionName = $_.Substring(1,18).Trim()
$item.Username = $_.Substring(19,20).Trim()
$item.Id = $_.Substring(39,9).Trim()
$item.State = $_.Substring(48,8).Trim()
$item.Type = $_.Substring(56,12).Trim()
$item.Device = $_.Substring(68).Trim()
$item
}
foreach ($session in $sessions){
#match for session name entered
if ($session.Username -match $ctxsession){
Write-Host 'Found' $session.Username 'on' $server 'with Session ID' $session.Id $session.State
#Kill session with ID and Server, with verbose switch
#rwinsta $session.Id /server:$server /v
}
}
}
}
}
workflow get-citrixlist1 {
citrixlist -servers $serverlist1
}
workflow get-citrixlist2 {
citrixlist -servers $serverlist2
}
workflow get-citrixkill {
parallel {
get-citrixlist1
get-citrixlist2
}
}