Changing key via MIDI controller

[JSmith1234567]

Hi.

I'm using a number of pitched loops in DP via Spectrasonics Stylus and various NI libraries.

I want to change keys mid-song, which I can sort of do via pitch-bend, but it is kind of awkward.

Are there pitch-bend values that relate to actual transpositions/keys, or is this different in the way that different VI libraries implement things?

Is there a better way of doing this?

Some way of sending some kind of controller to change the key with a single value or controller?

Thanks!