Wow, way to miss the point. If you have 10 applicants for 2 posts, 8 from one group and 2 from another and you have a quota that says you have to hire at least one from the second group, then what is the result going to be? If you have no quotas, then you will hire the two best qualified. If you assume that there is no intrinsic difference in abilities between the two sets, then there is a 20% chance that you will end up with one from the second set. If there is a quota, then there is a 100% chance that you will end up with one from the second set, meaning that there is an 80% chance that you will end up with someone less qualified with the quota than without.
This then leads back to an ugly feedback cycle, where people are aware that the person in the second group is there instead of someone more qualified (see the caste quota system in India for examples of this) and so they grow to resent people from that group and, importantly, don't trust the competence of anyone from that group. This then makes it harder for the competent people in the group, because now they have an extra layer of prejudice against them.
Now, if you want more members of the second group to be hired, then you need to look at the causes and address them. For example, do they encounter the relevant skills later? Are there hidden prejudices against them in hiring? Are they excluded or discouraged from participating in some relevant educational prerequisites?