ᐅ Connecting Ikea Expedit Shelves Together

I want to combine three Expedit shelves, two stacked on top of each other and one placed beside them. The whole setup is meant to serve as a room divider. I would like to connect the units so they don’t shift and also secure them to the wall. To clarify: since it is set up as a room divider, only the side needs to be attached to the wall, not through the compartments.

How do you do this with the hollow structure of the side panels?

I want to combine three Expedit shelves, two stacked on top of each other, and one placed beside them. The whole setup will be used as a room divider. I would like to connect the units together so they don’t slide apart, and also secure them to the wall. To clarify: since it’s set up as a room divider, only the side needs to be fixed to the wall, not through the compartments. How can this be done given the hollow construction of the side panels?

Why do you want to fix it to the wall? They are quite heavy and don’t usually slide when you accidentally bump into them.

Two stacked on top of each other? Which two exactly?

Because I want to make it safe, especially since my little son might climb up and could cause it to fall.
A 150cm (59 inches) high, 80cm (31 inches) wide structure (I think it's built with 2x4s) will have a 2x2 on top, which measures 80x80cm (31x31 inches).

If I had a climbing monkey at home, I would secure that shelf with barbed wire.
I’m afraid the idea won’t be met with enthusiasm. I find all craft attempts with Expedit too risky. Any attachment to the shelf that isn’t spread over a large surface area could easily rip out or break off. It’s better to invest the money in something that is not hollow inside.

You can see how this might look in houses where patterns are layered on top of each other... Extremely unattractive.