@develroo Check with your hardware (or tell us what it is and we can help you find it) to see if it contains a UUID field? When the PXE rom sends the first dhcp discover packet if it fills out the UUID field in the dhcp discover packet then you might be able to do something.
If that field is populated and unique per hardware model then you can dynamically switch between by either creating profiles in Windows 2012 dhcp or use isc-dhcp or dnsmasq both on your FOG server to make the dynamic changes.