Now on to the questions and issues. /dev/hda1 is (hd0,0) in GRUB naming terms. /dev/hda5 is (hd0,4) using that same logic.
You can use a chainloader, provided you can successfully point to a root partition containing a boot image. IF those conditions can be met, then these commands will work:
title Mandrake or Mandriva on /dev/hda5
Another note, you really do not need separate swap partitions for each distro. I have had as many as a dozen systems that all use the same swap partition - just obviously not at the same time! Since multibooting means you only run one system at a time, one swap partition can suffice. Does not hurt to have separate ones, but it is more work and it is overkill.
Another way to do this is to find out what the name of the Linux image is for each system and explicitly write entries that point right to what you need. If and once you get good at GRUB, you can do this on the fly, running GRUB interactively, editing and modifying existing entries, then you can change them once you are sure of the exact parameters.
find /boot/grub/menu.lst will tell you what partitions each GRUB menu is on. That can give you some clues. Then you can mount the partitions on one system, poke at the files, reading and possibly copying parts of the content, building one or more GRUB configuration files on one or more partitions. That gets into more advanced use of GRUB, so don't go there until you understand GRUB.
Check out this link: http://www.mepis.org/node/13445
and this one: http://www.gnu.org/software/grub/manual/grub.html to work with GRUB on SimplyMEPIS and with GRUB in general. Once you master using GRUB you can do all kinds of amazing things with it, but it does take both reading and practice to learn several of its major capabilities. These two links will get you moving in that direction if you review them carefully.