Just change the send type from Post Fader to Pre Fader and then set the original track's volume to zero (so it won't be in the mains)
That said, I'm struggling to understand your goal.
It kind of sounds like you are trying to apply parallel processing.
If that is the case, there is a much more straight-forward solution:
1. Put a plugin on your source track
2. In the upper left-hand corner, click on the splitter view
3. grab the hand/splitter tool and create as many parallel paths as you want for your processing. Add plugins to each path.