National conferences are pretty much passe for both the curia and conservative Catholics these days, but it didn’t prevent the suggestion that national scale efforts might be needed:
Since an effective apostolate on a national scale calls for unity of planning and resources, this sacred Synod decrees and orders that national offices for affairs of the press, films, radio and television be established everywhere and given every aid. It will be the special task of these offices to see to it that the consciences of the faithful are properly instructed with respect to these media. Likewise they should foster and guide whatever is done by Catholics in these areas. In each country the direction of such offices should be entrusted to a special committee of Bishops, or to a single Bishop. Moreover, lay(people) who are experts in Catholic teaching and in these arts or techniques should have a role in these offices.
And there is a role for the laity, we see.