I'm probably a little behind in my reading, so the correct answer may be too
late for a Pat on the Back, but here goes:

To solve the problem of being milk related and thus to avoid having an
incestuous relationship, you simply have to divide the donor milk by gender
(of the baby). Boys should only receive the milk of mothers of boys and girls
the mothers of girls' milk. In this way, the boys would never marry someone
that they were "related" to through receiving banked milk.

Did I win??!!

Kathy in NJ