display only one point for each ID

I'm working with a point layer (many many features) that has some attributes, like the elevation of each point.

I created a polygon grid (5 km x 5 km each cell) with an unique ID and I made an intersection of the point with this polygon. This way each point that belong to a certain cell has now the unique ID.

Now, how can I display only the point with the maximum elevation for each different IDs? What is the expression I have to put in the field calculator of the rule renderer?

So in other word, how can I put into formula something like:

for each "ID" show max("ele_feet")