Sorry, I misread your question. There is a way to do this, but it is not very elegant.
First, select the three surfaces of the slot, then copy&paste to create a Copy feature
Second, do the same with the surface of the cosmetic thread (make sure to select the geometry, not the feature itself) to create a second copy feature.
Third, create a trim feature, using the copied thread surface as the Trimmed Quilt, and the copied slot surface as the Timming object. You may have to use the arrows to flip the removal side, but that should give you what you need.
You can then hide the original thread, and you will see what you want. Basically, you won't be showing the actual thread on the drawing, but a copy which has been cut to suit the slot. It is a bit awkard, but it is the only way I know how to do this.
