How do you foreign key multiple tables that don't have any columns in common Such as the following 3 tables without adding columns to any of the tables?

Table 1: 

Create Table Person
(
PersonID Integer,
Name Char(50),
Gender char(6),
Primary Key(PersonID)
)

 

Table 2: 

Create Table Parents

(

ParentID Integer,

ChildID)

 

Table3: 

Create Table Spouse

(

Spouse1ID Integer,

Spouse2ID Integer

)