Is the LCR network strictly in series? No parrallel paths back to (-)? If yes, you want a spst(on/on) switch for each speaker filter. Switch the positive like you have shown. I'd probably turn off the amp to before switching the filter in or out.
Another way you can do it even simpler is to use a SPST(on/off) switch to short out the filter or not. [When the switch is "on" is parrallels a wire to the filter, the wire short circuits the filter so the filter is essentially not there. When the switch is off, the wire is open and not shorting the filter out].
More like this
___filter______________________
(+)-----------< > (+ speaker term)
----wire------ (switch) ----------