This is an interesting subject that is not that easy to solve. Currently you can automatically dispose samples according to their respective pitch in an instrument. This is possible because each sample is tuned and contains the information of the pitch.
Automating this process for velocities is not possible because the information of velocity is not memorized within a sample. What you can do is creating as many instruments as velocity layers. For example three instruments containing only the samples related to their respective velocities. You can automate the disposition of the samples for each instrument according to their pitch, and for each instrument you specify the velocity range. For example:
- instrument 1 is for 0 to 80, which is piano
- instrument 2 is for 81 to 110, which is mezzo-piano
- instrument 3 is for 111 to 127, which is forte
Then you create a preset comprising all instruments together. This way you can dispose quite easily all samples and you are able to process each velocity layer independently.