I am wondering if anyone could advise me on how to accomplish the below using code first in EF6

If I add the Table_3 as a List on to Table_1 & Table_2 in my entities. EF automatically generates a foreign key column for both tables in Table_3 instead of recognizing that they are of the same type.
My model classes are set as follows.
public interface IParent
{
int ID { get; set; }
List<Table_3> Children { get; set; }
}
public class Table_1 : IParent
{
[Key]
public int ID { get; set; }
public string Name { get; set; }
public virtual List<Table_3> Children { get; set; }
}
public class Table_2 : IParent
{
[Key]
public int ID { get; set; }
public string Name { get; set; }
public virtual List<Table_3> Children { get; set; }
}
public class Table_3
{
[Key]
public int ID { get; set; }
public int ParentID { get; set; }
[ForeignKey("ParentID")]
public virtual IParent Parent { get; set; }
}
EF code first generates the below

Edit
Just to let anyone having the same problems know
I have now resolved this by changing the IParent interface to an abstract class my classes now look like the following
[Table("ParentBase")]
public abstract class ParentBase
{
[Key]
public int ID { get; set; }
public List<Table_3> Children { get; set; }
}
[Table("Table_1")]
public class Table_1 : ParentBase
{
public string Name { get; set; }
}
[Table("Table_2")]
public class Table_2 : ParentBase
{
public string Name { get; set; }
}
[Table("Table_3")]
public class Table_3
{
[Key]
public int ID { get; set; }
public int ParentID { get; set; }
[ForeignKey("ParentID")]
public virtual ParentBase Parent { get; set; }
}
with a table arrangement of

this will work although it would have been nicer if the original could have been met.