Scripts

I'm almost finished creating a map, but I've run into a problem: I need to create a custom bonus for a set of artifacts, and I have no idea how to do it. The idea is that if a hero has the following artifacts: Necromancer's Helmet, Cursed Ring, Ring of Broken Spirit, and Necromancer's Amulet, then:

It guarantees that at the start of the battle, all creatures in the enemy army will be affected by the spells "Slow," "Misfortune," "Weakness," and "Curse." The effect lasts for 10 turns.

Please help.