easy to do with midimasher sitting between your controller(s) and traktor. there's no "controller range" option afaik for type=fader in traktor. if it had that, like it does out "out" types then u would be able to do it just within traktor i presume. u can use midimasher to just pass all data between traktor and your controller unmodified and just add in extra midi messages if needed for stuff like this
edit: midimasher does require some coding skills tho - if only simple ones. this config is one i did the other day for someone to fix the lpd8 issue of turning pad led's off when u want them kept on... http://midimasher.djism.com/lua/config/lpd8_ledfix.lua but apart from that just routes midi between the lpd8 and vdj.