Develop an application for the common OSs (Social Network App)

The project is basically a small social network but instead of connection users to each other, we want to connect users to companies. We do have a mockup. We need: - the coding We would prefer it in a multi platform environment like XAMARIN because: that reduces the workload we need to make some changes on our own later on we want to publish on the 3 main operating systems - the coding includes several functions like a newsfeed, searching for companies (via name-search and map-based) - the rest is quite simple - most important: we need an automatic user registration and a backend where we can administrate all users and the companies. Companies should of course be able to publish content which then appears in the user's newsfeed. Publishing, Corporate Identity etc. is not part of the job. If the cooperation is successful we would gladly outsource several other projects in the near future. At some point our app will need a webpage, an update and so on, you get the idea. We are looking forward to hear from you!