Entity Framework - 6, Parent Key propagation to grand child object - entity-framework

Question

public class Submission
{
public Submission()
{
this.VisitOccurrences = new HashSet<VisitOccurrence>();
}
public int SubmissionKey { get; set; } //PK
public string Version { get; set; }
public string ClientName { get; set; }
public string UserName { get; set; }
public DateTime SubmissionStartDate { get; set; }
public virtual ICollection<VisitOccurrence> VisitOccurrences { get; set; }
}
public class VisitOccurrence
{
public VisitOccurrence()
{
this.Observations = new HashSet<VoObservation>();
}
public int VisitOccurrenceKey { get; set; } //PK
//public int SubmissionKey { get; set; } //FK from submission . This is commented as this value inserted by EF in table. Refer to configuration below.
public string VisitConcept { get; set; }
public DateTime? VisitStartDate { get; set; }
public TimeSpan? VisitStartTime { get; set; }
public DateTime? VisitEndDate { get; set; }
public TimeSpan? VisitEndTime { get; set; }
public virtual ICollection<Observation> Observations { get; set; }
}
public class Observation
{
public int ObservationKey { get; set; } //PK
//public int VisitOccurrenceKey { get; set; } //FK from VisitOccurrence. This is commented as this value inserted by EF in table. Refer to configuration below.
//public int SubmissionKey { get; set; } // ***there is no relation on this column but I need to propagate value from parent class Submission to this grand child column when inserted Submission. What is the best way to do it?***
public string Element { get; set; }
public string ObservationConcept { get; set; }
public DateTime? ObservationDate { get; set; }
public TimeSpan? ObservationTime { get; set; }
}
public class SubmissionConfiguration : EntityTypeConfiguration<Submission>
{
public SubmissionConfiguration()
{
ToTable("Submission");
HasKey(p => p.Id).Property(p => p.Id).HasColumnName("SubmissionKey");
HasMany(p => p.VisitOccurrences).WithOptional().Map(m => m.MapKey("SubmissionKey"));
}
}
public class VisitOccurrenceConfiguration : EntityTypeConfiguration<VisitOccurrence>
{
public VisitOccurrenceConfiguration()
{
ToTable("VisitOccurrence");
Property(p => p.Id).HasColumnName("VisitOccurrenceKey");
HasMany(p => p.Observations).WithOptional().Map(m => m.MapKey("VisitOccurrenceKey"));
}
}
public class ObservationConfiguration : EntityTypeConfiguration<Observation>
{
public VoObservationConfiguration()
{
ToTable("Observation");
}
}
//Repository Method to insert Submission
public virtual void AddOrUpdate(Submission model)
{
Context.Entry(model).State = EntityState.Added;
Context.SaveChanges();
}
I have a Parent entity Submission, a Child entity VisitOccurrence and Grand child entity Observation. My configurations works When I inserted a Submission with child and grand child entities in it. All key columns populated in related tables. However, The above code inserts Submission and the identity generated in SubmissionKey is inserted in VisitOccurence and thus the VisitOccurenceKey in Observation table. But I'm looking for Configuration that could propagate SubmissionKey from VisitOccurence to Observation though there is no relation constraint added in database. please help.