Some one was going to propose it eventually ...

Create a new rule, called 'Surnames', with the following text:

Each family has a Surname, which is initially the same as their player name, and is listed in the GNDT. All Family Members who have this Surname are listed in the same row as their Surname. A Family can change any Family's Surname at any time in the one week following the passage of this proposal.

After a marriage between a Male and a Female Family Member, the Female Family Member takes the Surname of the Male Family Member and is transferred to that Surname's row.

I've reverted the illegal edition of this post's subject. Chronos.