In Studio One you could use the Gate... it has a trigger function. It is somewhat limited though. If I remember correctly Warren use Melodyne to create MIDI tracks to trigger drum samples. I use Steven Slates Trigger. Both those methods require a higher level of Studio One than Artist. If you do upgrade Studio One to a higher level where you get Melodyne Essential... you will get a good offer on their better editions of Melodyne. Just be aware of it, check Melodyne Editor/Studio out beforehand and if it seem like something you want, have the cash ready. It is a good deal and limited to two weeks. At least it was when I got it.
There are videos showing how Warren does it with Melodyne hear somewhere within your plapa academy account.