How do I create nested sub folders?

I am creating a multi site network and need to have nested subfolders (e.g. wedding, law, blog, photography, restaurant, …:wink: to group different types of sites.

http://www.mynetwork.com

http://www.mynetwork.com/wedding/site1

http://www.mynetwork.com/wedding/site2

http://www.mynetwork.com/law/site1

http://www.mynetwork.com/law/site2

http://www.mynetwork.com/law/site3

http://www.mynetwork.com/blog/site1

http://www.mynetwork.com/blog/site2

….

….

I’ve tried to do it myself and I’ve searched the wpmu plugins, but have not found a solution. Do you have a plug in that helps me create these nested subfolders? If not, could you shed a light on how I can do it?

Thank you,

Giovanni