Question How to make NPC execute command players can't do?

Hey, guys!

So, on my server, I am creating parkour, and at the end of each level there is an NPC which executes 3 commands:
- Heals the player (npc cmdadd heal)
- Warps player to next level (npc cmdadd warp (level))
- Gives player an effect (npc cmdadd effect @p minecrafteffect) 1000 2 true)

How can I make it that when a player without permissions to these can right-click the NPC and the commands work and are executed? Or is it not possible?