使用纯WinApi的儿童自定义“容器”控件

I would like to create a control (named HWND container) in a window (named HWND hwnd) that will hold other controls like a button (named HWND button) and an image (named HWND bitmap) avoiding the use of "static" standard class. It will contain some custom drawn controls whose messages will be handled in the main WndProc (I don't want to add another WndProc) and I would like at the same time to be able to call only once the function I would like to create a control (named HWND co