Set default folder in Google Drive do synchronize

I installed insync and set up my local folders that should be sent to Google Drive.
All information is loaded at the root of my GDrive, but I would like to do this in a sub folder, how do I do this?

I guess it’s not currently a feature and I’d like to do it too.

My workaround : First I set Insync to ignore syncing the root of GDrive. Then I create a subdir in the base folder and put everything want there. Also, I set the selective sync options to watch only my subdir.
The problem is that I always have to mind this setup, so I don’t make mess with my files.