Sort of. “Merit” is more a measure of those groups’ definitions of success. Calling it a meritocracy overly simplifies the circumstances for that success, often reinforcing the power relationships.
You can't. Merit -- including "success" or "accomplishment" -- is always a subjective value judgement. Even if there is an objective measure, the evaluation of the measure as something meaningful to measure (i.e., that the measure is one of merit or success) is a subjective value judgement.
And the dominant group in society is, pretty much by definition, the one whose judgement is most influential.
Then what is the viable alternative to achieving merit in the judgement of that group?