How to make it can deal 1 damage for all enemy in the range in melee

How to make it such that when dealing damage to enemy in sword slash, it allow to deal multiple enemy in the area, but it only can deal to each enemy per slash?

I making some sort of melee combat with combo animation, as each stage deal different damage, example like (stage 1 deal 0.1, stage 2 deal 0.1, stage 3 deal 0.2 damage).
I had add my sword with collision box for deal the damage.

The combo animation per stage have different animation timeline, so I can’t use delay to prevent multiple damage on enemy in 1 stage.
I assign the sword with bool variable can damage, and per animation stage will activate true, and once it detect any collision with enemy will set to false, but doing this only make it single target.

Any ideas how I can design such that, I can deal multiple target, but only deal 1 damage per animation stage?

Here hope this helps, you will still have to make a small logic for adding the combos but I already added the combo multiplier which multiplies a base damage.

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