On elektron machines it´s called conditional trigs.
On cirklon its called random gate mask.
Basically, I want a probablity parameter that will say if the current step will be triggered or not. I´m a new pyramid user, so maybe this is possible.
There is a midi effect called Chance (probability) in which you set the probability in percent of steps triggering. you can also automate this effect, making the chance that some steps triggering higher/lower then other steps.