How to get already opened object without open a new window?

Question

I saw this win32com start document.

http://timgolden.me.uk/pywin32-docs/html/com/win32com/HTML/QuickStartClientCom.html

And I got below code to start.

import win32com.client
o = win32com.client.Dispatch("Object.Name")
o.Method()
o.property = "New Value"
print o.property

I want use QXDM application with like this,

import win32com
import win32com.client
import pythoncom

pythoncom.CoInitialize()
QPST = win32com.client.Dispatch('QPSTAtmnServer.Application')
port_list = QPST.GetPortList
for i in range(0, port_list.PhoneCount):
            print("COM port name=%s status=%s mode=%s",
                          port_list.PortName(i),
                          port_list.PhoneStatus(i),
                          port_list.PhoneMode(i))
IQXDM = win32com.client.Dispatch('QXDM.Application')

This code make a new QXDM window. ( DispatchEX should be, but I don't want )

I want use already opened QXDM window but I don't know how.

I found this question : http://bytes.com/topic/python/answers/819283-how-recognize-ie-window-already-opened-using-win32com-extension

I cannot understand what is shellwindows_guid, and how to get that id, and is it right what I want.