You may be thinking about it backwards. You don't route a bus to tracks. Rather, you route the output from individual tracks to a bus, and control the level of the signal from each track to the bus.
One way to accomplish it in Sonar (there are several):
- Create a new bus (right-click in the Bus Pane, and choose "Insert Bus")
- Rename the bus "reverb"
- Add your reverb plugin to the new bus's FX bin
- On each track that needs reverb:
o Right-click on a blank part of the track pane (beneath the track's volume and pan faders) and choose "Insert Send", and select the "reverb" bus you created
o Enable the send (by checking the little box to the left of the word "Post")
o Set the level and pan of this track's send to the reverb bus