How to add checkbox group outside html form to model

I have this code

Razor

@foreach (SFD.Models.General.List.Customer item in Model.CustomerList)
{
  <tr id="@item.CustomerId">
    <td>@Html.CheckBox("CustomerId["+@item.CustomerId+"]")</td>
    ...
  </tr>
}

which generate html output

<input name="CustomerId[22394]" id="CustomerId_22394_" type="checkbox" value="true">
<input name="CustomerId[22394]" type="hidden" value="false">

the problem I need to solve is that checkbox group is outside form

@using (Html.BeginForm("Index", "Customer", FormMethod.Post }))
{
...
}

and therefore checkbox group values are not send after submit value. So my question is, how I can add these values to the submit request ? Maybe with jQuery onclick event ? What datatype property for checkbox group is suitable, it is for example an array ?

public int[] CustomerId;