But they are the same year group. So to engineer it, they'd need to know where William was applying.
While the UCAS process might not apply to William, it would to Kate.
So she'd have to have known before making her a level choices to make select the right courses, then have predicted what subject and where William was applying for, then done the same.
With an application into St Andrews by January when I don't think it was announced where William would go until summer.
I'm sure she put herself in the right places to meet him but most people in his year probably did this. I don't think you can engineer anything beyond that and it was largely coincidence that presented the opportunity.