Ok here is the code i'm using im still getting the unexpected 'In" error.

$domaingrp = "corp\desktop admins"
$Obj = GetObject("WinNT://" + $WSname + "/Administrators")
For each $GroupObj.Name in $Obj.Members
?$GroupObj.Name
$Dummyvar = $Dummyvar + GroupObj.Name
?$Dummyvar
Next
IF INSTR($Dummyvar,$domaingrp) = 0
?"Add group"
ELSE
?"Group Already Added"
ENDIF