With a hex pickup, it is possible to route separate strings to different audio plugins.
For MIDI, in the case of routing the 6th and 5th string separately, you will have to use MIDI hardware.
Otherwise you can use a standard guitar without hardware with the Midi Guitar plugin.
It works by frequency detection, not string detection. So you can route a selected range of bass (or any other) keys separately to different MIDI channels (If you are familiar with the Boss OC-3 octaver, it works exactly the same way for selecting octave notes).