Setting to Narrow Reception (Selectivity)?

[Dewey3]

I'm testing a GMRS/FRS TrunkRecorder, but I'm having overlap reception problems similar to the now closed #103. When one of the repeaters on the repeater frequencies go active, I get random pops on the surrounding interstitials. (Example, 462.675 goes active and 462.6625 and 462.6875 start receiving random pops). I'm currently using the squelch setting in my channelFile, because that seems to work better for me than the Signal Detector / signalDetectorThreshold. I'm not near any of the repeaters, so I doubt that it's a proximity bleedover or over-powering issue. With that said, is there a setting I can use in my json file to cause the SDR's frequency reception to be narrower?