Product Line Engineering (PLE) is a crucial practice in many software development environments where software systems are complex and developed for multiple customers with varying needs. At the same time, many development processes are use case-driven, which strongly influences their requirements engineering and system testing practices. In this paper, we propose, apply, and assess an automated system test case classification and prioritization approach specifically targeting system testing in the context of use case-driven development of product families. Our approach provides (i) automated support to classify, for a new product in a product family, relevant and valid system test cases associated with previous products and (ii) automated prioritization of system test cases using multiple risk factors such as the fault-proneness of requirements and requirements volatility in a product family. We performed a case study with an industrial product family in the automotive domain. Results provide empirical evidence that the approach is practical and beneficial to classify and prioritize system test cases in industrial product lines. The original paper can be downloaded from https://orbilu.uni.lu/handle/10993/43531}. Novelty is discussed in the submitted manuscript.