A group-based communication platform is configured to ascertain the relatedness of various work objects shared among users of the group-based communication platform. Moreover, the group-based communication platform may further receive and process work objects originating from non-users of the group-based communication platform, thereby further expanding the utility of the determined relatedness between work objects. These work objects (or encrypted representations of these work objects) may be indexed and stored in association with the group-based communication platform, thereby enabling users to search for and retrieve work objects originating from a plurality of work object sources simultaneously, and based on various characteristics of those work objects and the determined interrelatedness between various work objects.