Strongly type your view so it as an associated model that is a custom object that contains both lists. Note such an object is often referred as a "viewModel".
Example:
Your viewModel:
public class MyViewModel
{
public List<X> Added { get; set; }
public List<X> Removed { get; set; }
}
Your controller:
public ActionResult Index()
{
var viewModel = new MyViewModel
{
Added = ...,
Removed = ...
};
return View(viewModel);
}
Your view:
@model XXXXX.MyViewModel
...