Existing product requirements form a rich source for domain requirements analysis in software product lines (SPLs). Most existing domain analysis techniques depend on domain experts' experience and manual operation to identify the commonalities and variabilities of product requirements. They often demand a high level of manual effort and a large up-front investment, which can present a prohibitive barrier for SPL adoption. This study proposes a model-driven approach to semi-automatically derive domain functional requirements (DFRs) from product functional requirements (PFRs). Based on the linguistic characterisation of a domain's action-oriented concerns, the authors apply Fillmore's semantic framework to functional requirements and define metamodels for PFRs and DFRs. Functional requirements of existing products are constructed as corresponding PFR models. Following the proposed merging and refinement rules, the authors approach automates the transformation from PFR models into DFR models by merging the same or similar PFRs and analysing their commonality and variability. The resulting DFR models can serve as an initial basis of the SPL. The authors demonstrate the authors approach using an example of a home security system (HSS) SPL and give a preliminary evaluation. The authors approach provides a rigorous model-based support for DFRs development and complements existing domain analysis techniques with less time and effort.