I haven't run this, but I think it'll work:
$NameToZap = 'JDiMaggio'
$USERNAME = 0
$SESSIONNAME = 1
$ID = 2
Get-Content -path c:\temp\server.txt |
ForEach-Object{
$x = quser /server:$_
for ($i = 1; $i -lt $x.count; $i++){ # skip the header
$y = $x[$i].split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)[$USERNAME..$ID] # get the 1st 3 columns of data
if ($y[$USERNAME] -eq $NameToZap){
logoff $y[$ID] /server:$_ # log off the session id
}
}
}