Redmine

Is there any way to restrict the access to a folder for a given subgroup?

For example, in a project, I have 3 users a,b,c and the architecture of folders
in the repository:

f1 |_ f11 |_ f12 |_ f13

I want that the folder f12 is accessible only for a and b and all
the others folders are accessible for all user.

Thanks a lot for your help.