Animation Action Trigger/Affect

Hey all,
I am wondering how I can change the “affect” from “selected element” or “class” to “interaction trigger.”
I want four items and when I hover my mouse over that item, that item animates. IE, when I hover over item 1, 1 animates, but 2, 3, and 4 do not. When I hover over 3, 3 animates, but 1, 2, and 4 do not.
When I apply “selected element” to my animation, Item 1 animates regardless of which item I’m hovering over (1, 2, 3 or 4).
When I apply “class” to my animation, all 4 items animate together.
But when I try to change affect to “interaction trigger” I get a message saying I can’t. I get the error message “This option is only available to actions applied to the elements that are triggering the action.”
Thanks for the help!

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