[XP] Question on Guild Hall Quest System

[Despedia]

Hi y'all, I need some help with my quest guild system, let me skip straight to the question.
Say, my Quest Giver has a list of 4 quests, and after I've finished one I'd like the chosen quest to be removed from the choices list. How do I set up my event to accomplish this?
I kinda know how variables work, after every quest a I command that a constant of +1 is added to a hidden value to determines if the player is ready for the next set of quests. This value has to be equal to 4 to access the next page. I don't want the player to abuse this system and redo the easiest of the 4 quests 4 times and access the next page.
Thanks in advance for the kind soul willing to help me! 

[Pokey]

Use a quest system(if there are any)