5 QB license linked together

I have a QB license that I use for creating invoices, end of the month statements, ect. I want to add 4 more computers for my employees to use to create invoices and email them only. Can I buy 4 licenses for that purpose. 

OR

I have a QB license that I am using. I need to add this to another computer. Can 2 people be working at the same time if the computers are linked.