If you have got floppy, you can do it easily. Otherwise you may need to get a bootable DVD image and dd it to the slave HDD. I haven't had a chance to try the second option , so not sure whether it will work, but it should.
Another option I think is that, dd the first CD image to master HDD (which should boot), and then copy images to a directory in the second HD. I believe images will do, though I don't remember it exactly (two+ years passed :-P). If it don't work try the NFS installation style of rpm copy (All rpms inside RPMS folder). Boot the master HD and then choose the installation from HD.
I believe the second HD will also be listed when you choose installation from HD and you just need to point to the directory created. Anaconda will automount it. In case it didn't do the needed, copy it to a partition in first HDD itself.
I would also like to see the replies here to see the other options.