Making DropDownLists depend on each other

In my MVC4 application I have two models being User and Schedule that look like this:

public class User {

    public int UserId { get; set; }
    public string Name { get; set; }
    public string FullName { get; set; }
    public string Email { get; set; }
    public bool isAvailable { get; set; }
}

public class Schedule 
{
    public int ScheduleId{ get; set; }
    public DateTime Date { get; set; }
    public int UserId { get; set; }
    public virtual User User { get; set; }
}  

Now I want to make a page that will display a table with the days of this month and next to the day a DropDownLists (per day) with all the users with isAvailable to true in the list. This page will be used so that an admin can make a schedule (I would also be open for improvements on how to implement this) and select one user per weekday. I want to make it so that once a user is selected in one DropDownList that this user disappears from the other DropDownLists.

The Controller and View looks as follows now, controller:

public ActionResult Schedule()
    {
        ViewBag.UserId = new SelectList(db.Users, "UserId", "FullName");
        return View();
    }

View:

@model IEnumerable<seashell_brawl_corvee.Models.Schedule>

@{
    ViewBag.Title = "Schedule";

}

<fieldset>
<legend>@ViewBag.Title</legend>

@using (Html.BeginForm())
{
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <table class="table">
        <thead>
            <tr>
                <th>Date
                </th>
                <th>Select person
                </th>
            </tr>
        </thead>

        @{ DateTime dt = DateTime.Now; }

        @for (double i = 0.0; i < 60.0; i++)
        {
            dt = dt.AddDays(1);
            if (dt.Date.DayOfWeek != DayOfWeek.Saturday &&
                dt.Date.DayOfWeek != DayOfWeek.Sunday)
            {
            <tbody>
                <tr>
                    <td>
                        @dt.Date.ToLongDateString()
                    </td>

                        <td>
                          @Html.DropDownList("UserId", String.Empty)
                        </td>               

                </tr>
            </tbody>
            }
            else
            {
            <tbody>
                <tr></tr>
            </tbody>    
            }
        }
    </table>

    @TODO: Submit button and controller POST action that reads the dates and names 
           from the dropdownlists, puts them into arrays and then into the database.
}

</fieldset>

I know I need JavaScript/JSON to make the DropDownLists dependent on each other and have names no longer displayed once they are selected, but I do not know how exactly I would go to accomplish this. I would be very grateful if someone could help me further!