How can I manage dual boot with Foreman?

I have about 80 machines that need to boot both CentOS 7 (for most applications) and CentOS 6 (for one stubborn app). There seems to be very little documentation out there on getting Kickstart files that won't clobber each other; is there a guide or any pointers on installing two Linux OSes side-by-side with Kickstart?

The machines (due to our external DNS management) will need to have the same DNS name whichever flavour they boot, so am I going to have to use two Foreman instances to manage them?

It'll be a pain if the only way to do this is to manually put a second installation on each!