The development of software components for autonomous driving functions should always include an extensive and rigorous evaluation. Since real-world testing is expensive and safety-critical -- especially when facing dynamic racing scenarios at the limit of handling -- a favored approach is simulation-based testing. In this work, we propose an open-source graphical user interface, which allows the generation of a multi-vehicle scenario in a regular or even a race environment. The underlying method and implementation is elaborated in detail. Furthermore, we showcase the potential use-cases for the scenario-based validation of a safety assessment module, integrated into an autonomous driving software stack. Within this scope, we introduce three illustrative scenarios, each focusing on a different safety-critical aspect.