yep! make sure you don't install any bootloader with SuSE, then boot into mandrake and change the lilo configuration. should work fine. by the way you can use the same swap partition for mandrake and suse, 'cause they won't use it both at the same time, saves some disc space.
.-=~ iluvatar ~=-.
ps: in case you don't know how to edit the lilo configuration file, come back here