Maybe something like this (I did not test this)
 Code:
If NOT @LOGONMODE
	Break On
Else
	Break Off
EndIf
Dim $RC
$RC=SetOption("Explicit", "On")
$RC=SetOption("NoMacrosInStrings", "On")
$RC=SetOption("NoVarsInStrings", "On")
$RC=SetOption("WrapAtEOL", "On")

Dim $objWshNet, $strComputer, $objGroup, $objMember

$objWshNet = CreateObject("WScript.Network")
$strComputer = $objWshNet.ComputerName

$strComputer ?

; group to remove user from
$objGroup = GetObject("WinNT://" + $strComputer + "/Administrators")

; Loop through all names of members of group
;For Each $objMember in $objGroup.Members
;	$objMember.Name ?
;Next
;"Error " + @ERROR + " - " + @SERROR ?

; I think There is no KiX code to replace this:
; suppress errors, e.g. trying to remove the builtin Administrator
; account from the Administrators group will fail.
; On Error Resume Next

; loop through all members of the Administrators group of type users
For Each $objMember In $objGroup.Members
	If $objMember.Class = "User"
		; Administrator cannot and should not be removed
		If NOT $objMember.Name = "Administrator"
			; remove the user from Administrators group
			$objGroup.Remove($objMember.ADsPath)
		EndIf
	EndIf
Next

Maybe also look here:
Hey, Scripting Guy! How Can I Compare the Memberships of Two Groups?