[Delmobile]

I tried to think of a family/which pairing that sounded "right" and came up with something on the lines of "The McGowin family, which had always controlled local politics..." or "The Smith family, which continues to increase in number but not in wealth..."

But I think both examples treat the family as a "thing." You wouldn't say, "But my greatest thanks must be reserved for my family, which never stopped supporting me through this often difficult and trying time." Well, I wouldn't anyway. :)