Giving Class-Exclusive Abilities to Other Classes

Hello, guys

Aiming for my next mod.

Quick question: can you, for example, allow a druid to have Turn Undead or a fighter to have Bard Song or a Cleric to have Find Traps/Detect Illusions buttons in their quick-action bar?

I'm asking this because I don't have the faintest idea of how de UI works for classes abilities.

Thanks.