Hi Ines and Andreas
both of you might be interested in the following Article:
Anheier, Helmut K. / Romo, Frank P. (1992) Modelle strukturellen Scheiterns in Policy-Netzwerken
in: Journal für Sozialforschung, 32. 1992, Heft 1. P. 33 - 60.
I don't know about any English versions of the Article, but your e-mail addresses indicate that both of you speak German.
The article focuses on structural failure specifically in policy-nets, but the approach Anheier an Romo use could be inspiring for your field of research too.
Good Luck