Making adjustments to a logistics network to keep it in good condition is a major challenge. Logistics assistance systems are regularly used to support this process. The authors have developed such a logistics assistance system that identifies, evaluates, and proposes promising actions to the decision-maker. A simheuristic approach, utilizing a data-driven discrete event simulation in combination with meta-heuristic algorithms is used for this purpose. A typical feature of such systems, however, is that the possible changes to the logistics network are predefined by the respective logistics assistance system. In order to address this aspect, the authors have developed a novel method that allows for modeling, integration, and simulation of user-generated actions. The method is based on a domain-specific language for the formal description of actions in logistics networks, allowing domain experts to model actions without having in-depth programming knowledge.