Add OR logic to SieveProcessor

[Reza-Noei]

Hi, I want to add conditional filters including OR login on my data:

suppose that we have following entity:

public class User 
{
     public string FirstName { get; set; }

     public string LastName { get; set; }
}

I want to have the ability to write an expression which acts like this:
context.Users.Where(P => P.FirstName.StartsWith("Reza") || P.LastName.Contains("No").ToList();

I didn't found the answer for such a situation.