How to hide options within a submenu?

Basically, I want to make a naming screen with just a few preset names to chose from; of these names, you can also chose a matronym with them. Basically, I want to make sure that the player can’t pick the equivalent of John Johnson for their name, and while I’m willing to go to release without that if necessary (I mean, names like that do happen in real life), it would make certain meant-to-be-serious dialogue come off sillier than intended. It’s not a total dealbreaker, but I’d rather avoid the situation to begin with.

I’m currently using a submenu for naming, but I realize that it may not be ideal for this purpose. Dunno how else to handle it, though!

Please explain the whys behind what to do as well, I don’t retain information nearly as well otherwise.

Have two different choices (create two name variables) one that asks the gamer to make a first name choice and the other to make a last name choice.

Something like:

*create first_name '""
*create last_name “”

Then in your story

What is your first name?
*set first_name Larry
*set first_name Moe
*set first_name Jack
*goto Lastname

*label Lastname
What is your last name?
*set last_name Pep
*set last_name Rudje
*set last_name Clyncye

*goto blablabla

That’s should just be possible with a basic *if within a choice.

*label given_name
        *set name "John"
        *goto surname_name
*label surname_name
    *if (name != "John") #Johnson

That said, I’d strongly recommend against it. 1) People like to play as themselves, and that means having the option to put in their own names. 2) People that aren’t going to take the name seriously aren’t going to take the game seriously at all, so it’s usually worth it to at least leave the option.