How to create multiple lists of uploadable files

I have a form with the following:

         <input type="file" name="files" multiple class="form-control" />

I can capture the list of images like this:

        var files = HttpContext.Request.Form.Files;

My question is this:

What if I have two lines:

         <input type="file" name="files1" multiple class="form-control" />

         <input type="file" name="files2" multiple class="form-control" />

I don't think using HttpContext.Request.Form.Files will work, because it looks to me that it returns only one list.

If I'm right, what can I do to get both lists from one form?

I'd appreciate any advice!