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.