Hide GM only information?

Hello! I was wondering if it was possible to add a section in the character creation screen(or even other sections that could benefit from this idea) where world builders can enter information about a NPC that Franz will know and draw off of, but players and NPCs wont be able reference the information.

For example, Gortash in BG3 being a Bane follower. No one but a select few know and NPCs shouldnt be able to skim that information off the bio to tell the player about it.

Or hidden POIs where a hidden cultist lair is that isnt known to the surrounding residents.