Register and Resolving Dependencies on Request Based on Param (Autofac WEB API) - asp.net-web-api

Question

I have an Application with autofac dependency injection and I wanted to use a specific dll extension based on the parameter I have on the request.
Here's my global.asax where I initialize autofac.
var containerBuilder = new ContainerBuilder();
containerBuilder.RegisterApiControllers(Assembly.GetExecutingAssembly());
containerBuilder.RegisterModule<ExModule>();
var container = containerBuilder.Build();
container.Resolve<IArtigoErp>();
Here's the autofac module where I load register my DLL's
public class ExModule : Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
//Load DLL1 from folder and register it
RegistaDepedencias<IArtigoErp>(builder, "DLL1");
//Load DLL2 from folder and register it
RegistaDepedencias<IArtigoErp>(builder, "DLL2");
}
private void RegistaDepedencias<T>(ContainerBuilder builder, string NomeDll)
{
RegisterDep<T>(GetEnumerableTypes<T>(NomeDll), builder);
}
private void RegisterDep<T>(IEnumerable<Type> types, ContainerBuilder builder)
{
foreach (var t in types)
{
builder.RegisterType(t).As<T>();
}
}
private IEnumerable<Type> GetEnumerableTypes<T>(string NomeDll)
{
return Directory.EnumerateFiles(Path.Combine(HostingEnvironment.ApplicationPhysicalPath, "Engine"))
.Where(x => x.Contains(NomeDll) && x.EndsWith(NomeDll +".dll"))
.Select(x => Assembly.LoadFrom(x))
.SelectMany(x => x.GetTypes()
.Where(t => typeof(T).IsAssignableFrom(t) && t.IsClass));
}
}
Both my DLL's have a class that extend from IArtigoErp.
So the ideia is, based on the parameter I get on my request, I want to run the method in either DLL1 or DLL2.
Example:
if(param == 1)
_artigoErp.GetLista(); // In DLL1
if(param == 2)
_artigoErp.GetLista(); // In DLL2
EDIT 1:
The parameter comes from the post method as it follows (Guid IdLoja)
public class ArtigoController : ApiController
{
private readonly IArtigoErp _artigoErp;
private readonly IArtigoLoja _artigoLoja;
public ArtigoController(IArtigoErp artigoErp, IArtigoLoja artigoLoja)
{
_artigoErp = artigoErp;
_artigoLoja = artigoLoja;
}
[Route("PostArtigos")]
public CallResponse PostArtigos([FromBody] Guid IdLoja)
{
}
}
I guess we can also process this in the begin_request method in global.asax
Thanks in advance.