UEFI / BIOS network booting

How can I add information into config.boot so that devices will choose the correct file during network boot?

I am wanting to determine EFI or BIOS and push the correct file.

		class "pxeclient" {
		    match if substring (option vendor-class-identifier, 0, 9) = "PXEClient";
		    if substring (option vendor-class-identifier, 15, 5) = "00000" {
		        bootfile-name "undionly.kpxe";
		    }
		    elsif substring (option vendor-class-identifier, 15, 5) = "00006" {
		        bootfile-name   "ipxe32.efi";
		    }
		    else
		        bootfile-name   "ipxe.efi";
		    }

I have taken this from https://wiki.fogproject.org/wiki/index.php?title=BIOS_and_UEFI_Co-Existence