棱镜：新项目与新模块和模块之间的通信

I am working on a Prism/WPF Project and I already have a framework that contains three modules all of which implement a MVVM pattern. Each module has it's own user interface in which the user can give some data and this data can then be communicated to the server. Now, my question is: do modules in a Prism application only refer to different parts of a user interface? Can I also create a module that would implement the communication with the server or should I create another project for this? Let's say the communication with the server is implemented in a module, and I have a class called UserAccount and all other modules that have a user interface need to have access to it. Should the UserAccount be a part of the server communication module or a part of the Infrastracture? I am working on a Prism/WPF Project and I alrea