Can we implement physical DIP switches to route different differential signals?
Sure you can switch the signals (double pole and double throw DIP switches are also out there).  

The traffic may get garbled up if you have A from one bus and B from the other bus connected during switch over.  A DIP switch is not much different than a connector as far as the electrons are concerned.

https://www.google.com/search?q=DPDT+DIP+switch&amp;tbm=isch