The notion of a genre system typically connotes sequences of interrelated communicative genres. This paper suggests that we can find other types of relationships among genres. Data from a field study in a large emergency room illustrates how doctors, nurses, and clerical staff routinely combine document genres not only in sequences, but also in accumulations achieved by proximity or through movement. The combinations of genres add flexibility to the ER staff's genre use and allow them to employ individual genres for several purposes. The data allows us to explore how organizational members manage the tension between continuity in genre expectations and a need for flexibility in regard to paper-based and digital media. In addition, it demonstrates how end-users often tinker with genres' materiality and form in the process of affording or constraining combinations among specific genres.