In the situations where salesman gets control of another salesman customers, the new salesman can't see the old salesman invoices. There might be a situation where the new salesman takes control only on opened orders I suggest to have 3 levels of global security:
1. At Customer, Order and Invoice history. This is what currently Elliott supports. Salesman can see orders and invoices only if they match the Salesman on the customer file and the user security.
2. At Customer/open order level only. In this case salesman can see opened orders belong to the customer even if the salesman is not on the order but the order belongs to the customer of the salesman, but can't see invoices that don't belong to the salesman.
3. At Customer level. Salesman can see orders or invoices belong to the customer This will be useful if salesman is replacing a retired salesman.
In the perfect solution you can assign the Global setup on the Salesman level at the user security.