You’ve been able to parameterize web servers in web (performance) tests since 2005. When you do this, it sets a context parameter that you can update to retarget to a different web server.
Well, you can take advantage of that in load tests. Just right-click on the run settings, select “add context parameter”, and add a context parameter of the same name to the run settings. You can use that to override the web server settings in the web performance test (look at the bottom):