Finder not showing Windows server networks
Have you added each Mac to the Windows workgroup?


System Preferences > Network
Select the relevant network interface from the sidebar (Ethernet, Wifi etc)
Click 'Advanced' 
Click 'WINS'
Enter the name of the Windows workgroup in 'Workgroup:'
Click the + button and enter the IP address of your Windows server in place of 0.0.0.0
Click 'OK' and 'Apply'