If the client can provide a real time API where associate permissions can be validated, the details of the integration should be worked out with the client during the implementation. The following is an example of what might be needed.
Creating a BM User for Each Store for Endless Aisle
Specifying the BM Credentials for an Endless Aisle Store
Permission Groups for Endless Aisle Store Associates
Managing Permissions for Endless Aisle Store Associates
Creating, Assigning, Modifying Endless Aisle Store Associates