I'm not sure if I'm understanding what you're asking...
But if I'm understanding properly, you're asking if you can connect two hard drives using the same IDE cable?
If you are, then the answer is yes, just as you said, provided of course, that the IDE cable has two connections available (most do) - It sounds like yours does as well. Alternately, you can also connect a hard drive or a CD-ROM/DVD-ROM on the same cable. Some devices don't work well together though, even if they are the same type (two hard drives, two cd-rom's, etc..)
If running into problems, test them separately, and if they work, then double check your settings (maybe they're both set as master which won't work), try setting them up manually (as master and slave) instead of leaving them on cable select. Even after trying this, some devices STILL will not work together. Older burner's were a real pain about this, some would work, but the burner DEMANDED to be the master - I have MANY HDD's that refuse to work together, yet still work fine on their own.
It shouldn't matter at this point, but if you're using an older PC (and I MEAN OLD - mostly pre-pentium), IRQ/COM settings may also become relevant.