Question about Item Drop

Hello, my apologies if I wrote this on the wrong forum.

I want it so that a quest item drops from random enemies I fight but only once. Like I fight enemies in a map and then they have a chance to drop that item but they only drop it once not again.

And I want it so that it disappears from my inventory after I turn it in.

Well, you might be able to do that by using events. Like have an event on the map you fight said enemy that changes the fights once you obtain a certain item. Have two versions of the enemy that drops the item, one that does and one that doesn't. Also have troops set for both of them and have the event turn the troops that do drop the item off once you obtain it.

Another way would be to set your troop to "always" drop the item, but as an event instead of the usual "official" drop, an event having a specific condition, like a switch, which is turned off in the event itself so it won't repeat.

Edit: you would have to use said event to announce the item has been dropped, though.