Max height of a children become height of all children

Hello Webflow community,

This is my first real project on webflow.
I’d like the div height of all my collection item to be the height of the heightest collection item for the testimonials of my client page.

Do someone know how to achieve this without javascript ?

I can’t use flex for the layout of my collection list otherwise all my 5 elements are in column while I only want 3 column.

Here is my site Read-Only: LINK
(how to share your site Read-Only link)