Scenarios are valuable for supporting communication among system developers in the initial phases of requirements engineering. But the problem of how to fruitfully deal with large informal or semi-formal scenario collections consisting of weakly structured texts is still a key research issue. In this paper we report on a novel approach of automatically structuring textual document collections. We focus on its application to scenario management and discuss how structuring scenarios can help to support the analysis and maintenance of scenario collections. To evaluate the approach we present a case study within a concrete software engineering effort.