C# - can I derive from class with generic base type?

Question

Intro

I am creating an ASP.NET Web API application with Entity Framework. What I need to do is return different representations of the same resource for one URI, depending on user role. For example, api/employees/1 will return two different objects for admin and standard user:

Standard user

public class EmployeeBasic 
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

Admin

public class EmployeeExtended : EmployeeBasic 
{
    public decimal Salary { get; set; }
}

The idea and the attempts

For each resource representation, I will need to provide some related classes, let's say Sort Models for example. I was wondering if it is possible to use generic types and inheritance to create a generic repository methods for related representations. I thought of the following way of doing this:

1. Create some base interface for Sort Models:

    public interface ISortModel<out TBusinessEntity> 
    {
        //
    }
   

2. Create generic SortModel as a base type for all sort models

     public abstract class SortModel<TDBEntity, TBusinessEntity> : ISortModel<TBusinessEntity>
     {
          // Database sorting
          public abstract IQueryable<TDBEntity> ApplyToQuery(IQueryable<TDBEntity> query);
   
          // Local sorting
          public abstract IEnumerable<TBusinessEntity> ApplyToLocal(IEnumerable<TBusinessEntity> localList);
   
          // ...
          // Some private logic (expression mappers, etc.)
    }
   

3. Create sort model for basic resource

    public class EmployeeBasicSortModel : SortModel<DBModel.Employee, EmployeeBasic>
    {
        public int FullName { get; set; }
   
        public override IQueryable<DBModel.Employee> ApplyToQuery(IQueryable<DBModel.Employee> query) 
        {
            // implementation
        }
   
        public override IEnumerable<EmployeeBasic> ApplyToLocal(IEnumerable<EmployeeBasic> localList) 
        {
            // implementation
        }
    }
   

4. Extend the basic sort model and add sorting for the extended resource properties

    public class EmployeeExtendedSortModel : EmployeeBasicSortModel //, ... Is it possible to somehow do that?
    {
        public override IEnumerable<EmployeeExtended> ApplyToLocal(IEnumerable<EmployeeExtended> localList) 
        {
            var partiallyOrderedList = base.ApplyToLocal(localList);
   
            // Add extended sorting
        }
   
        // ... ?
    }
   

5. Use the above classes to create generic service:

    class EmployeesService() 
    {
        public IList<TEmployee> GetAll<TEmployee>(ISortModel<TEmployee> sortModel)
               where TEmployee : BasicEmployee
        {
            // implementation
        }
    }
   

The problem

When I thought about it for the first time, it seemed pretty simple. But when I started implementing this, I couldn't figure out the way to implement Step 4. Either I am missing something in my C# knowledge (which is quite possible) or this is not possible in the way I am trying to do this.

So the question is: can I create a base class with generic type, derive from it with basic resource as a type and derive one more time with the extended class?