To help further clarify the difference between the words 'communication' and 'communications' I would like to offer the following. However, before I do allow me to qualify my comments. I am a vocational educator specialising in the development of managers, and other trainers. Therefore, effective use of, and a sound understanding of communication and communications skills is essential.
Communication is the act of communicating, or to communicate. Communication refers to the process of sharing ideas and information between individuals or groups. Communication is about language, questioning skills, listening skills, rapport building, non-verbal and verbal techniques, etc.
Communications is the method used to engage in communication, eg telephone, email, writing, radio television, etc.
So to clarify why you have organisational or marketing communication or communications marketing/organisational communication is about sharing the ideas, concepts, gathering information. Marketing/organisational communications is about the medium mix.
So if you wish to communication networks you need to be speaking and listening to people, or if you wish to have a communications network call your local telephone technician.
I hope this helps you understand your English and its correct use.
Re
Adrian