amenity=univ./coll./research_institute: How to tag a mixed campus?

I am in the process of gradually mapping all educational campuses/terrains in my town, and have run into an interesting issue. While for most educational facilities the situation is quite clear (a school with its grounds, a university with its campus, etc), I also have one area that is shared by a research institute, a university, and a college. The separate buildings are tagged properly, but I’m unsure how the area as a whole (which has a name and distinct boundary, and where the institutions share parking spaces, grounds, and access roads) should be tagged.

The amenity values for the three institutions (college, university, research_institute) exist, but none of them seems applicable to the whole area. There does not seem to be a usable generic ‘education’ amenity value, or is there?

I think nowadays landuse is better than amenity for such cases. And you can pick the main feature for mixed cases - the same as you do with shop when it’s a mix of different types.