You would have to have two separate databases on the server. Probably the easiest way to do that would be to use Windows Server 2012 R2 and set up Hyper-V
http://www.sitepoint.com/hyper-v-virtual-machine-tutorial/ and then set up two VMs.
On the workstations, obviously, you could just set up different accounts or run a VM which would then not necessitate logging off and on. But, the different accounts would be cheaper.
I am not completely sure if you could connect separately by connecting to the virtual switch on the Hyper-V.
As far as two people using the same workstation, are the two employees or physicians working at different times?
