The Dutch Catholic Church has an archbishopric and six suffragan dioceses under it as well as a Military Ordinariate.
An archbishop stands alone at the head of the archdiocese, but he is not the "boss" of his fellow bishops or their dioceses.
If a non-bishop is diocesan administrator, he will attend meetings of the bishops' conference, but is not a voting member.
Therefore, Ad van Luyn was the President and Frans Wiertz the Vice-President (the two 'seniores "among the seven bishops).
Today Hans van den Hende is President and Jan Liesen is Vice-President.