Yes, that makes sense.... This shouldn't be too horribly hard to do... You'll have to play with it a little bit....
You are going to want to make up a new routine, and call up the routine with a "test mode" tag.... This tag would also disable the "normal" routine that operates the outputs, to make sure that only the specified output comes on at one time. You may also want to come up with a routine to put zeros into all outputs before calling up the test routine, but I'm not sure if that will be necessary or not.
Next, you are going to create a control list, and put each one of the output tags into the list. Since you aren't going to be using any ladder logic to control the outputs, when you call up the test routine you can just write a 0 or 1 to the output tags directly.
Hopefully this makes some sense... I haven't had to create this setup from scratch yet, so I may be leaving some key points out.... I've just been using a setup that another programmer put together. Hopefully someone else will chime in as well.