Conditional Anaconda Kickstart Partition or rpm package install based on dmidecode

I have a two kickstart files one for a Virtual Machine another for a regular machine. The only difference between the two files is the partition size for the Virtual Machine should be much smaller. It doesn't look like the kickstart scripting language has an "if" statement that allows to make this conditional. Through searching it sounds like I can make some checks in the %pre section of the kickstart. Is this the correct way to do this? How would I use the %pre section to create some conditional value to partition the harddrive based on whether or not I'm working with a Virtual Machine.

thanks,
Robert