In this work, we show that bioinspired function-sharing can be effectively applied in engineering design by abstracting and emulating the product architecture of biological systems that exhibit function-sharing. Systems that leverage function-sharing enable multiple functions to be performed by a single structure. Billions of years of evolution has led to the development of function-sharing adaptations in biological systems. Currently, engineers leverage biological function-sharing by imitating serendipitously encountered biological structures. As a result, utilizing bioinspired function-sharing remains limited to some specific engineering problems. To overcome this limitation, we propose the Function-Behavior-Structure tree as a tool to simultaneously abstract both biological adaptations and the product architecture of biological systems. The tool uses information from an existing bioinspired design abstraction tool and an existing product architecture representation tool. A case study demonstrates the tool's ability to abstract the product architectural characteristics of function-sharing biological systems. The abstracted product architectural characteristics are then shown to facilitate problem-driven bioinspiration of function-sharing. The availability of a problem-driven approach may reduce the need to imitate biological structures to leverage biological function-sharing in engineering design. This work is a step forward in analyzing biological product architectures to inspire engineering design.