In this work, we explore an alternative: a modular systems approach, where instead of engineering the catalytic species for selectivity, we separate the roles of catalysis and selection (Fig. ). A nonselective catalyst may be used, and "prosthetic" selectivity (selectivity not mediated by the catalyst) is imparted by molecular recognition of one enantiomer by a Supramolecular Protecting Group (SPG), preventing its reaction in a manner analogous to a covalently-bound protecting group. Using SPGs to control reactivity, where molecular recognition prevents access of reagents or catalysts to a substrate -or a region of a substrate -has been reported for some time, including for regioselectivity and kinetic resolution reactions, particularly following a landmark publication by Gibb et al. applying this principal to control a simple, otherwise-unselective, ester hydrolysis reactions. Indeed, the approach might be more well-recognised but for the diverse range of terms used to describe it ('Supramolecular Inhibitors', 'Noncovalent Auxiliaries', 'Shadow Mask', among others). However we are not aware of examples incorporating this into a catalytic system employing an unselective solid catalyst, which may be recycled.