Shameless plug... (see what I did there? )
 
Sidechain Mixer gives you some additional routing options, like sending from a bus back into a track. And of course you can also route from track-to-track to create a track bus.
 
So in the example where bouncing from a bus to a track would be required, you can simply drop Sidechain Mixer into the track's FX bin and route the bus output back to the track in realtime, no bounce required.

WOW that sidechain mixer, and its free!!!!! WOW!!! Surprised/disappointed not to have seen it mentioned in any official cakewalk videos?! Guess it pays off to hang out in the forum :D
Thanks to whoever created it!!! 

Well, TBH I'm hoping that enough people find this useful so that CW is convinced there is demand for this workflow. Enough to convince them to add a per-track option to make that track's input available to other outputs and sends.

Kev999
I would also prefer that "PRE" would actually be displayed as "PRE" instead of just greyed-out "POST", as it used to be in earlier versions of Sonar.

Oh god yes.