The only way to do this is to set up another location. Each location can have its own account. There are other issues to consider before doing this. Inventory tracking, employee management, etc. are then seperate. Also one of the employees will have to log out and log in under that location. It may be easier to transfer the money based on the employee sale report.
For more info on setting up locations, have a look at this article: Manage Multiple Locations with Square.
