How to get Count in Lambda

I have three models (Applicant, Meeting, City) and I joined three of them. I want to get Count by grouping MeetingId in Applicant model. Here are my models and method I use for populating Dropdownlist in Controller. So, like the "Expired" property in the Controller, how can I obtain the count for the MeetingId by grouping on "TotalMeetingById" property?

Applicant Model:

public class Applicant
{
    public int ApplicantID { get; set; }
    public DateTime? SubmitDate { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }   
    public int MeetingId { get; set; }
}

Meeting Model:

public class Meeting
{
    public int MeetingID { get; set; }
    public string MeetingName { get; set; }
    public DateTime MeetingStartDate { get; set; }       
    public DateTime? MeetingEndDate { get; set; }
    public int? TotalParticipant { get; set; }
    public int? MeetingCityId { get; set; } 

    public int? ParticipantCityAId { get; set; }
    public int? ParticipantCityBId { get; set; }
}

City Model:

public class City
{
    public int CityID { get; set; }
    public string CityName { get; set; }
}    

Controller:

private void PopulateDropDownList()
{
    var meetingsQuery = repository.Meetings
        .GroupJoin(repository.Cities, m => m.MeetingCityId, c => c.CityID, (m, c) => new { m, cA = c.DefaultIfEmpty() })
        .SelectMany(z => z.cA.Select(cA => new { m = z.m, cA }))
        .GroupJoin(repository.Cities, m => m.m.ParticipantCityAId, c => c.CityID, (m, c) => new { m.m, m.cA, cB = c.DefaultIfEmpty() })
        .SelectMany(w => w.cB.Select(cB => new { m = w.m, cA = w.cA, cB }))
        .GroupJoin(repository.Cities, m => m.m.ParticipantCityBId, c => c.CityID, (m, c) => new { m.m, m.cA, m.cB, cC = c.DefaultIfEmpty() })
        .SelectMany(t => t.cC.Select(cC => new { m = t.m, cA = t.cA, cB = t.cB, cC }))
        .Select(
            m =>
                new
                {
                    CityID = m.cA.CityID,
                    CityName = m.cA.CityName,
                    MeetingDate = m.m.MeetingStartDate,
                    MeetingName = m.m.MeetingName,
                    NameofMeetingCityIdA = m.cA != null ? m.cA.CityName : null,
                    NameofMeetingCityIdB = m.cB != null ? m.cB.CityName : null,
                    NameofMeetingCityIdC = m.cC != null ? m.cC.CityName : null
                })
        .OrderBy(x => x.CityID)
        .AsEnumerable()
        .Select(
            i => new
            {
                Value = i.CityID.ToString(),
                DisplayValue = string.Format("{0} ({1:dd MMMM yyyy})", i.NameofMeetingCityIdA, i.MeetingDate),
                Expired = i.MeetingDate < DateTime.UtcNow,
                TotalMeetingById= ??? >>> I cannot get the total count for the related MeetingId at here
            }
        ).ToList();

    var selectItems = new List<MyHelpers.MySelectItem>(meetingsQuery.Count);
    foreach (var record in meetingsQuery)
    {
        var item = new MyHelpers.MySelectItem
        {
            Text = record.DisplayValue,
            Value = record.Value
        };
        if (record.Expired)
        {
            item.Class = "disabled";
            item.Disabled = "disabled";
        }
        selectItems.Add(item);
    }
    ViewBag.MeetingData = selectItems;
} 

Here are sample data for models:

Applicant:

 ApplicantID : 100
 SubmitDate : 01/11/2013
 Name : Christof
 Surname : Jahnsen 
 MeetingId : 1

Meeting:

 MeetingID : 1
 MeetingName : City Information Days
 MeetingStartDate : 01/01/2014       
 MeetingEndDate : 02/01/2014
 TotalParticipant : 2 (for example) 
 MeetingCityId : 500
 ParticipantCityAId : 501
 ParticipantCityBId : 502

City:

CityID : 500 / 501 / 502
CityName : London / Paris / NY

Update -----------------------------------------------------------------------

Razor:

@Html.LabelFor(m => m.Applicant.MeetingId)
@Html.MyDropdownListFor(m => m.Applicant.MeetingId, ViewBag.MeetingData as List<MyHelpers.MySelectItem>, "---- Select ----",
        new { name = "meetingId", id = "meetingId" })
@Html.ValidationMessageFor(m => m.Applicant.MeetingId, null, new { @class = "ValidationErrors" })

Controller:

public ViewResult Add()
{
    PopulateDropDownList();

    ApplicantViewModel model = new ApplicantViewModel
    {
        Applicant = new Applicant(),
        Applicants = repository.Applicants,
        Lookups = repository.Lookups,
        Cities = repository.Cities
        .ToList()
        };
        return View(model);
    }

[HttpPost]
public ActionResult Add(ApplicantViewModel model)
{
    ApplicantViewModel viewModel;

    if (ModelState.IsValid)
    {
        model.Applicant.SubmitDate = DateTime.Now;
        repository.SaveApplicant(model.Applicant);
        PopulateDropDownList(model.Applicant);
        return View("Completed", ViewBag.ApplicantId = model.Applicant.ApplicantID);
    }
    else
    {
        // there is something wrong with the data values
        PopulateDropDownList();
        TempData["message"] = "Please try again.";
        viewModel = new ApplicantViewModel
        {
            Applicant = new Applicant(),
            Applicants = repository.Applicants,
            Lookups = repository.Lookups,
            Cities = repository.Cities
            .ToList()
        };
        return View(viewModel);
    }
}