Best way to apply changes to some resources

If I’m deploying 20 windows web applications using a module that deploys all of these applications with the base configuration and then I want some of these apps to have virtual application blocks defined in the site_config block, what is the best way to achieve this?

So, I currently have a module that defines the settings I want on all 20 web apps. When I run apply, the calls the module and iterates through all of the 20 apps and sets their configuration. But I want two of these web apps to have virtual application blocks, but I don’t want this to occur on the other 18. I’m currently using azurerm_resource_group_template_deployment with a depends_on. But I’d like to use the built-in virtual_application block that is now available in the azurerm_windows_web_app resource.