I was certain about this at first, but the more I think about it the more uncertain I get.
The site is offering 28 educations, and each education is X times a year. There are three different education-related pages on the site:
I don't want the overview page and the calendar page to compete against each other. If that's the case, the overview page is most important.
Should I add Rich Snippets (a.k.a. Structured Data) on all three pages?
I think, your first (overview page of the different educations) and third (calendar page) page should be the same, namely the homepage. According to this i would add it on two kinds of pages:
Google's John Mueller recently weighed in on this:
In general, the structured data on a website or on a page should be specific to that particular page. So it shouldn't be something where you kind of say, well, this is a review of our business in general, and therefore, we'll put it on all of the pages
So you should only mark up a piece of structured data on one page, and it should be on the page that covers that as the main topic of the page.