Targeting the 75th percentile for a few job families while the rest stay at median?

Our pay policy is market median for everyone. I am at a health technology company in Sweden, about 950 employees. Leadership now wants to position machine learning and security roles at the 75th percentile, around 60 people.

I can price that easily enough. What I am unsure of is how to hold it inside one structure. Options seem to be a separate set of ranges for those families, a market premium on top of the standard range, or simply putting them a grade higher.

Which of these have you used, and how did you explain it to the families that stay at median?