Monitor a site on a node that has more than one site.

Does dropping IIS not cause a 'standard' monitor (with appropriate receive string) to fail? Are you currently running an http(s) monitor on that pool or a different monitor type?

I'm confused by your response to Vijay's post. Your original post indicates you want to monitor on a port other than standard 80 or 443. (Technically, by default the health monitor will connect to the port defined by the pool member itself.) Using a alias port is the way to have the monitor connect to a port other than that defined by the pool member. So if your Devs have a separate site running on a different port of same node, alias port will achieve that (as long as it's the same port on all nodes).

If it's a situation where the Devs need to keep the web service up (where it would respond to a monitor request), you can utilize the 'receive disable' string. This would allow the service to remain up, but the BIGIP would mark the pool member as disabled if the text of the monitored file contained the 'receive disable' string.