Here is one that works with Universal Groups and AD. You must know the distinguishedName of the group.

fnADComputerInGroup("CN=TestGroup,OU=Groups,DC=my,DC=domain,DC=com")
 
Function fnADComputerInGroup($sGroupDN)
    Dim $objSys,$objCom,$aMemberOf,$sMemberOf
    $objSys = CreateObject("ADSystemInfo")
    $objCom = GetObject("LDAP://"+$objSys.ComputerName)
    $aMemberOf = $objCom.GetEx("memberOf")
    For Each $sMemberOf in $aMemberOf
        If $sMemberOf = $sGroupDN
            $fnADComputerInGroup = NOT 0
            Exit
        EndIf
    Next
    $fnADComputerInGroup = NOT 1
EndFunction