You're a good deal better at explaining your question than the majority of people who post on this site! ;-)
To the best of my knowledge, no version of Windows Explorer has an option to toggle on-and-off a display of the contents of sub-folders, within the host folder itself. Some third party utilities (which provide alternatives to Windows Explorer) might have an 'include subfolders' option but I've been unable to track down any such utility for you.
Your best option might be to create a new folder, somewhere on your computer, called (for example) 'Unsorted'. Then, repeatedly using 'select all' (as explained above) copy the contents of A, B, C, etc to that folder. Then you can choose whether to access 'Albums' (with its subfolders) or 'Unsorted', depending upon your needs. (Of course, having two copies of everything will mean that your files will take up twice as much disk space but, with the massive sizes of hard drives these days, that might not be a problem).
Chris