Subwoofer crossovers


I want to use my 2 JL113's with my 2 channel as well as my surround sound system. The JL's do not have an LFE input only L&R inputs. I think I need a crossover for the 2 channel system that I can shut down via remote so only the setting in the surround sound processor control the sub in theater mode. I use the right inputs for 2 channel stereo & the left inputs in a T configuration for mono with the surround system but the settings for 2 channel restrict the sub too much I think. I would like two differant crossover settings.
Any ideas or am I making this harder than it is.
Thanks for your input.
hevac1
The idea of monitors and subs is appealing, but I wonder about the dynamic range of monitors. I think they might be great for most of the music I enjoy, small jazz and chamber groups, but what about the occasional excursion into large orchestrations, e.g. Mahler's 2nd. I admit that I haven't listened to many of the newer monitors.

db
I my experience deep and solid bass response is more critical to realistically render "small jazz" (with bass and drumkit), than large orchestration. In fact, nowhere do I need my subs more than on small jazz.
I think Edorr may have misunderstood my question. I use a pair of 15" subs with room correction, and I agree they are important for portraying small jazz groups. I was asking about the ability of monitors to handle the dynamic range of a large orchestration in the frequency regions not handled by subs.

db
Post removed 
Post removed