Ramey Rieger (X) Apr 6, 2015:

Yes, you're right then IF you're looking for something somewhat 'headier' than working groups, then perhaps you can say 'commission/directors/panel or board'

Diana Obermeyer (asker) Apr 6, 2015:

To be honest, I'm a little wary of using BOD. I apologise, as I should have mentioned this: The different congresses and conferences are not organised by the same body, they only cover similar subjects. The Board of Directors is a legally constituted group with the authority to manage the company. But I have no indication that this would be the BOD of the organisation which organises the event and cannot see real policy decision being taken in relation to an event. As far as I can see, all these committees relate to the specific event. This is why I think the executive committee is closer to the intended meaning of Vorstand in this case.

Ramey Rieger (X) Apr 6, 2015:

You say various congresses so perhaps there are varying committees/panels, but then all of them would be in the plural. However, the board of directors is not necessarily the executive committee. Maybe you can get around it by using the heading:
COMMITTEES:
Executive
Organiz/sational
Scientific/academic
Board of directors

Diana Obermeyer (asker) Apr 6, 2015:

That did cross my mind, because I really can't make sense of the plural form otherwise. But I don't have a definite clue :) I'm not very sure about a suitable collective term for these, either.

Lancashireman Apr 6, 2015:

Any clue from the font or indentation? Maybe the Organisatorischer Ausschuss and the Wissenschaftlicher Ausschuss are the two Ausführende Ausschüsse.