Hello everyone, 

I bring a solution for all the businesses that use the POS module and need to hide information to their cashiers.

With all the different needs that every business have in terms of security, multiple customers had the same question about the permissions regarding the POS and how to hide the different sessions and show only the assigned one for that employee.

In Odoo is completely possible with the developer mode tool. Just need to follow this steps: (This solution was tested on v15 and v16)

1. Activate the developer mode

2. Go to the POS module

3. Click on the debug button

4. Look and select the option "View Record 
Rules"

5. Create -> Name: Only Assigned POS -> Model: Point of Sale Configuration -> Rule Definition (Domain Filter): [('employee_ids.user_id.id','=',user.id)] -> Save

Try it with different users assigned to an speciffic POS and you´ll see it´s 100% functional.