Yes, but how you want it to work depends on whether or not you want to use plugins:
No-plugin approach: Equipped items allow the player to use a specific skill (added to their skill list). So the "Fire Rod" would give the player a skill called "Fire Rod" but it'd have to be selected from their skills/spells/whatever menu rather than the item menu.
Plugin approach: Not sure if a plugin exists for the vintage (FF1/FF4/FF6 approach--select item from equipped items, use for effect) but any plugin that replaces the basic attack and/or adds an effect (unleash) to basic attack can be used for something like this. This is the approach I'm using in my game just because I think it makes more sense than flipping to the item menu just to use your Fire Rod properly.