Many organizations providing products with common features wish to take advantage of that similarity in order to reduce development and maintenance efforts. Their goal is to move from a single-system development paradigm towards a product line approach. However, this transition is not trivial and requires a systematic scoping phase to decide how the product line should be defined, i.e. what products and features should be included and thus developed for reuse. Currently available product line scoping approaches require huge upfront investments in the scoping phase, consuming a lot of time and resources. Our experience has shown that small and medium enterprises require a lightweight approach to decide how the existing products are related to each other so that their potential for reuse can be estimated more easily. In this paper we present a conceptual solution and early tool support enabling companies to semi-automatically identify similarity within existing product configurations.