Is there a "Folder" mod?

Is there a modification where you can essentially create a folder in a Forum? This "folder" would be like a subforum within a subforum (I hope this makes sense)

For example:

Spine Surgery Forum

Spinal Fusion (subforum)​

Folder (that contains pertinent articles / publications on Spinal Fusion)​

 

I haven't seen anything like that. I had to make two different forums sections:

Turbo Information:

Turbo Tech Articles (no posting)
Turbo Tech Questions

This way i had one subforum which is closed to posting that has all of my articles in it and another subforum for questions.

 

Thanks, hotwheels.