1. Let say that the repository for the customer attachments is called
"Customer Attachments" and has id : 400003
2. Create a data partition constraint of type 'View' on 'Attachments' table with the following constraint:
Type : View
3. Assign this data partition constraint to a user with 'Customer' access type.
Users with this access type can not see anymore the attachments in the internal repository, they can only see attachments in the repository with repository id : 400003
Note: you can set the data partition at user level, at access type level or at role level