control knobs for a driver to be controlled from test class?

Dear All,

Is it always the case that the TOP test class can control/manage the control knobs of sequences only? I mean, I want to override/control some parameters of driver class from top test class, can this be done? If yes, how can that be done? because top test class stimulates only a sequence, so how would the control knob of driver be controlled from top test class? any guidance will be helpfull.

Thanks