WebApi2: Custom parameter binding to bind partial parameters

I have a webApi2 project and an other project, in which I have my Model classes and a BaseModel that is a base for all Models, as following,

public class BaseModel
{
    public string UserId { get; set; }
}

All the other models are derived from my BaseModel.

In webapi I have my CustomerController as following,

public class CustomerController : ApiController
{
    [HttpPost]
    public GetCustomerResponseModel Get(GetCustomerRequestModel requestModel)
    {
        var response = new GetCustomerResponseModel();

        //I need only the UserId coming from the BaseModel is binded from request headers
        var userId = requestModel.UserId;

        //I want all model data except UserId is binded with default model binding
        var customerData = requestModel.CustomerData;
        var someOtherData = requestModel.SomeOtherData;

        return response;
    }

    [HttpPost]
    public AddStockAlertResponseModel AddStockAlert(AddStockAlertRequestModel requestModel)
    {
        var response = new AddStockAlertResponseModel();

        //I need only the UserId coming from the BaseModel is binded from request headers
        var userId = requestModel.UserId;

        //I want all model data except UserId is binded with default model binding
        var stockInfo = requestModel.StockInfo;

        return response;
    }
}

Every request that comes to CustomerController has a "UserId" header in request headers and I need a ModelBinder or ParameterBinder or some functionality that binds only the UserId from request headers without touching the other model parameters. I mean model parameters except UserId are to be binded by default..

I don't want to use AOP or interceptors or aspects.. Is it possible to bind only UserId with an asp.net functionality like model binders, parameter binders, etc.