I'm not sure if this is possible or not. I'm wondering if using the command line options and df.exe it's possible to write a batch file that will defrag all drives, then defrag all the freespace on all drives, all one right after another.
As it is, if I want to do this with all four of my drives/partitions, it's a process of checking back and running the next partition, etc, several times.
I found some command help, but it didn't appear to have the capability.