Modify startup assemblies using the minimal hosting model

Is there a way to modify the startup assemblies using the minimal hosting model?

In ASP.NET Core 5 I would say the following (where `hostBuilder` is an instance of `IWebHostBuilder`):

```
hostBuilder.UseSetting(WebHostDefaults.HostingStartupAssembliesKey, string.Join(";", assemblies));
```

With the new minimal hosting model I tried saying:

```
builder.WebHost.UseSetting(WebHostDefaults.HostingStartupAssembliesKey, string.Join(";", assemblies));
```

However this throws a `NotSupportedException` and that I should use `WebApplication.CreateBuilder(WebApplicationOptions)` instead, but I can't see an option to specify the hosting startup assemblies.