In software product families, the full benefit of reuse can only be achieved if traceability of requirements to architecture, components and further down to source code is supported. This requires automated tool support for tracing from the abstract features of the product family to a set of concrete features and source code of family members. We extended a commercial software tool to support top-down as well as bottom-up traceability in product families, from the family feature map all the way down to implementation files. At the code level, both newly developed and commercial-off-the-shelf components are accommodated. The tool has been validated by (bottom-up) filling the tool?s reuse base with features, components, documentation files, etc. from six related products in the Next Generation Network service domain, and next deriving a seventh product from this reuse base.