ok, first, swap partitions can be shared, so you don't need to make a new one
alright, second, i take it you are not going to make a /boot partition separatately? you can do that, but redhat might complain and you may need to set aside a 100 meg /boot partition
this is probably what you will need to have your partitions look like
/dev/hda1 swap
/dev/hda2 suse root
/dev/hda3 redhat root
if you redhat doesn't care about the /boot partition, then make sure you choose to use the lilo boot loader
as for how to go about splitting your partition, i don't think disk druid can resize partitions; if you have windows lying around, you may want to look into Partition Magic
in Suse, you can use a partitioning tool called qtparted from
http://qtparted.sourceforge.net/ to resize your reiserfs partition (note: gnu parted and reiserfs tools required)
otherwise, you say you want as many distros as possible, go and download mandrake linux (or at least the first disk) and use their partitioning tool which is able to resize partitions quite well
good luck!