Allow restricted users to see all documents they have access to

Question

We're hosting our content/files in our Office365 OneDrive/Sharepoint online document library.

I have a few external consultants whom I would like to have access to sub-folders of our files, but not parent folders. I can create the users and add them to a group, but they have to always navigate directly to a link to folders they have access to.

Is there a way they could list all of the subfolders in the hierarchy and browse as though they can see only their own content?

For example, given the following scenario:

root/project-A/item 1/   <-- No access
root/project-A/item 2/   <-- Has access
root/project-B/item 1/   <-- No access
root/project-B/item 2/   <-- Has access
root/project-C/item 1/   <-- No access

If I grant access to a consultant on "item 2" for both projects A and B, is there a way the consultant can simply browse to root/ and see only the following folders?

root/
root/project-A
root/project-A/item 2/
root/project-B
root/project-B/item 2/

(basically all content they don't have access to can't be seen.)

Answer 1

As far as I know, it is not achievable.

In SharePoint Online, it is the default behavior that users can only see the items which they have at least View Only permission.

If you give the external users access to the root site level, they will have access to all items in this site since all lists and libraries inherit permission from the site. You will need to create unique permissions for all the other lists or libraries in the site collection.

So I would suggest you use the external sharing link on items to avoid messing up permission settings.

References:

Customize permissions for a SharePoint list or library.

External sharing overview.