Folder access level for read and write

Folder Level access

I have a requirement. to create a 2 folder i.e. (Sub -Folder as SD, MM, ) and root Folder as SCM with User (A , B,)

I need to give all 2 Sub- folders access to User A (since he is developer)

I need to give 2 folder access to B (i.e. SD MM) SD folder for Read and MM folder for Write

But B users has to give report viewing access to SD folder reports and need to save as in MM folder

Note : He should not have to save in SD folder. While saving the report only in MM folder has to be enable.

Please help How to disable saving report in SD folder for User B

Thanks in Advance

Regards,