You mean keep Chapters One, Two, and Three in the first post and then Chapter Four in a separate post? If so, you can do that although some readers might be confused why you have it like that. If you checked the other stories in the forums, most people have chapters separated by post. I think you can easily copy and paste Chapter Two and Three in separate posts.
Hope this helps! Sorry if this seems I'm forcing you, I was offering a suggestion that would make readers less confused where to find the chapters.