Do you have vCenter...
Connect to the vCenter web access...https://ip_of_vcenter/
Click on 'Log Into Web Access'
From there they can browse to the servers they need and get a console, or you can generate a Virtual Machine Shortcut. you will see the link on the right hand side under commands. That will generate a URL that you can give to them that will take them directly to the console of the selected VM. All you need to do is download a plugin!
Hope this helps!