Group nested membership and user rights

Hi,

I have main shared folder "Folder1". Under that is sub-folder Folder2. Under that is sub-folder Folder3. So, folder structure is like following: Folder1 - Folder2 - Folder3.

One of my domain user has read rights on Folder3. I need to find out group nested rights by which group membership user has valid rights? I can check Effective permission on Folder level, and it will show me read, modify or full rights, but I cannot see which group membership gave valid rights.

Is it available any File sharing tool for this, or any script?
thnx!