Commonalities

Rachel and Leah;
Hannah and Penninah;
Sarah and Hagar (therefore Issac and Ishmael);
Ahinoam, Maachah, Bathsheba (therefore Amnon, Absalom, Solomon (therefore 300/700)
...ad nauseum right up to the present.
Primary and secondary (even tertiary) families do not mix, do they?
They surely make chaos out of already challenging primary families, don't they?