You can only have 4 primary partition, but the 4th would be the extended partition, which contains the extended partitions that you see. On some computers, the boot partition should be on a primary partition. You could make the 1st partition the boot partition of your first install, the second primary partition the swap partition. Use this swap partition for all of the distros.
Then start adding your next partitions as extended partitions. Let the installation program do the partitioning, by choosing to manually partition during the installation. If all of the distro's are of equal importance, equally divide up the remainder of drive space among the installations.
Only write to the MBR on the first install. You don't want a case of dueling distro's on your hands, so only install the boot loader on the first installation. Red Hat's mkbootdisk script allows you to create a mini-cd boot image. 'mkbootdisk --iso'.
So install either RH9 or FC2 first and produce this boot cd before continuing with other installs.
I wish Mandrake's script did this, However with Mandrake you can create a rescue disk, which has a boot from HD menu options 'mkrescue --iso'.
In my opinion, Grub would be the better boot loader to use in your case. If a mistake is made in the menu.lst file, and one of the distro's won't boot, you can use tab-completion to locate the correct partition and boot up that way. (
I am speaking from experience on this point!