Is there an API for Android that will find other people nearby running the same app? For instance, if you were to perform a "scan" it tries to find other people running the same app nearby. Would it be possible to perform the same task across multiple OS (Android, iPhone, Windows, etc.)? Or would the best way be to just have the app communicate to a server your location and have a server-side app that pushes a list of others nearby??? My goal is to find an easy way to eventually transmit data between two devices contigent on those that are nearby.