Incorrect rights nesting

[DarkCorner]

I'm new to Truenas (Core) setup and can't properly enforce rights on SMB folders.
I have created these datasets:

• Work
• Work/Sales
• Work/Accounting
• Work/Interchange
• Work/Management

I then created the groups:

• Sales
• Accounting
• Interchange
• Management

All are associated with the corresponding datasets.

I then created a "Top" group which is associated with the "Work" dataset.
I then distributed the users in the various groups; the user "Ken" belongs to the Top group only.

What I want is that Ken can access all the underlying datasets starting from the Work alone without having to insert it in all the groups.
Instead from Windows Explorer Ken sees all the shares (and not just Work), but then can only access Work.

I don't understand how to set the rights on Work and on the underlying dataset without affecting the settings of the latter for the related groups.