Adapting a gamebook to multiple players

This is my first question, so I am truly sorry if it is nonsense. So, I am a newbie to RPG, however I used to play gamebooks (Fighting Fantasy) and I really enjoyed them.

I want to test if my group of friends would like to play RPG, but I don’t have time to learn a real system and I don’t know if they would really enjoy it.

Thus, I am adapting a gamebook for us to play. Of course I will develop more the story, creating new characters, monsters, giving them more options as a truly rpg. But keeping the mechanics very simple.

However, I am having a problem right now.

In the gamebook, there is an attribute called faith. You get your faith level by rolling a dice and adding 1 to the result. And a faith test is when you play 2 dices, add a modificator to the result (as it may be a hard test), and if the result is lower or equal to the player’s faith lever, he has passed it. Otherwise, he fails on it.

However, I can’t think how I could adapt these to multiple players.

Let’s suppose a situation where If the single player have success in the faith test and see a ghost that chats with him.

How could I adapt these to like 2-3 players, as most in the story they will be together?

I thought about each one doing the test, and if at least one passes on it, the ghost would show. But I don’t think that would be good as it would be very easy to the group to pass on the faith tests.

Thank you so much for your response and sorry for my bad English, is not my mother tongue. If I didn’t make myself comprehensible, I will gladly try to explain better my question.