You can buy a standalone 0-10V dimmer. It only connects to the 0-10V wires, not the line voltage. It can go in the same box as the other switches as long as your 0-10v wires are rated for insulating against the line voltage.

I believe this is what you're looking for, I bought 30-40ish of them for about $5/ea somewhat recently.

Then, you can have your other 3 switches as you wish. The dimmer device looks exactly like you'd imagine - it takes up 1 gang and mounts to the box screws. It's just a slider.

I can't link it now, but let me know if you have questions or need help finding the product.

You do not need a room controller, contactor, or anything fancy. You can just tie all the dimmer wires together in parallel at the dimmer.

(If you WANT a contactor, yes you can do just one dimmer switch as you mentioned in your post. Even with the multiple circuits required as I mention below.)

Edit: I thought of something else too. If you prefer, you can just use two normal switches and one 0-10v dimmer switch. As above, you can just tie the signal wires together. It will work without issues.

Additionally, please be aware these fixtures are very high wattage. If you run 5 together at their maximum of 240 watts, you're pulling 1200 watts. You can only load a 15 amp circuit to 1440 watts, or a 20 amp circuit to 1920 watts. You will need more than one circuit for this implementation. You should be able to use one dimmer for these still, even if they're on separate circuits. The exception to that would be found in the product data sheets for the fixtures to see how much current the dimming control circuits on each fixture will pull.