MVC 4 RouteValues object containing a List

.NET
1

Hey guys.

I am currently have the following model that contains all the GET parameters my method requires:

public class RequestModel
    {
        public List<int> clients { get; set; }
        public DateTime time { get; set; }
        public int Duration { get; set; }
        public double Rate { get; set; }
    }

But now I need to use the object in a redirect and output it as route values

return RedirectToAction("Index", "Appointments", (AppointmentRedirect)TempData["returnUrl"]);

This works fine for each object in the object, except for the List. The List output is like this:
clients=System.Collections.Generic.List`1[System.Int32]

I need the output to be something like this:
clients=1&clients=5&clients=2

What would be the best / easiest way to achieve this?

Thanks