I don't remember if you said what keyboard you're using, but MIDI keyboard controllers often have ZONE buttons that are used to define zones (or ranges of keys) on the keyboard and then toggle the zones on or off as desired. Each zone can be set to a different MIDI channel. If you define two or more zones that span the entire keyboard, assign each zone to a different channel, and apply different amounts of pitch bend to each channel, you can play notes that are shifted by different amounts depending on which zone you've got activated, such as
- Zone 1 - Channel 1 - Pitch Bend = 0 cents,
- Zone 2 - Channel 2 - Pitch Bend = +25 cents, and
- Zone 3 - Channel 3 - Pitch Bend = +75 cents.
You could also use a single zone and channel, and perhaps program some buttons to send different pitch bend amounts, but this would mean that when you applied a given amount of pitch bend it would affect all notes which were currently playing on that channel. That's why you'd really want to use different channels.
That also brings me to another point, which is that if you play a note on one channel with one amount of pitch bend, then play another note on another channel with a different amount of pitch bend while continuing to hold down the previous key, the keyboard is now set to the other channel such that when you release the first note it will send its Note Off message on a different channel than its Note On message had used. In other words, you're going to have problems trying to play live. This wouldn't be an issue if you're playing back sequences from tracks in your DAW, because you can program the Note On/Off events on whichever tracks you want.
Now, if you only ever need to shift certain notes-- that is, certain notes of the scale will never be shifted, but other notes will need to be shifted by some amount-- then it might be doable live using note filters in addition to applying different amounts of pitch bend to different channels. In that case you might not need to use the ZONE buttons on the keyboard at all, since you might be able to define the zones with the tracks in the DAW and note filtering.