Register each branch of the company in the CRM as a Client. In addition, you can add the city or street where the branch is located to the name so that you can recognise the branch at a glance in the client list.
In addition, you can link parent and subsidiary branches via the Links to other clients panel (this will be enabled by the Administrator in Settings → Extensions → Evidence of client relations).
Thanks to this, each branch can be taken care of by a different salesperson and you can record communication at individual branches separately.
Video to watch here: