Determine if a WebService is running?

Hi everyone!

I have an application that should call an webservice that can reside on any computer in my network. I use the SetUrl() to set the acutal location of the Webservice but as I don´t know which URL the WebService resides on I would like to have a couple of different URL:s to choose from. Now I´m wondering if it´s possible to determine if a WebService is running without making an actual call to one of the interfaces? Something like this:

MyWebService* GetWebService()
{
   bool bIsRunning = false;
   while( bIsRunning == false )
   {
        MyWebService* pService = new MyWebService();
        pService->SetUrl(strURL);
   
        // Check if WebService is running????
        bool bIsRunning = pService->IsRunning();             < ----- THIS IS WHAT I NEED HELP WITH
        if( bIsRunning )
            return pService;
    }
}