Probably the simplest method would be to put all of your gtr tracks in a folder, and then use something like Sleepy Time's StereoChannel Center x-over to mono-ize the low frequencies.
http://bedroomproducersblog.com/2014...eepy-time-dsp/
There are probably multiple different VST's (and JS) out there that can achieve that...
Alternatively you could get all fancy with a frequency splitter that sends the lows to channels 3/4, and then route that to a bus track, but I'd just stick with a tool that's made for the job.