Ordering folders and documents

I have a bazillion folders and documents that I use with Pages (and some with Numbers).

I write newsletters for many clients including 10 in the same field (I use the same stories as the clients are not located near each other and it's a local sort of niche for me). I have a folder I call Pet Images and inside that folder are a bazillion images of pets doing various things.

When I use an image in the newsletter I put it in a folder inside the Pet Images Folder for the month the newsletter went out. So September 2016 for example had 10 pet images that I used in this months newsletter. I don't want to reuse any of the same images for at least a year. So now I have all these folders for the various months but they are not grouped together, they are spread out alphabetically with all the images. Is there a way to move the all those "month" folder to be at the top or bottom of the list, with the various image files that are also in the same place?

Hope this makes sense.

Susan