Is it possible to create custom braille tables for nvda


Hi all.
I don't own or have access to a braille display but I am trying to help some friends.
First of all sorry if this has been asked before.
As the subject says, I am wondering if we can modify a braille table for our needs.

For example, in modern Greek braille, if a letter is accented we add dot 5 in front of the Greek character.

But some people don't want to see it at all so I was wondering if we could change this.

As you can understand, this is a matter of preference. Some people want to see the accented letters and some not.
So probably the best solution would be to have 2 Greek tables. One with the accented letters and one without.
So what can I do about this?
Is it a liblouis issue or is it an nvda issue?
I hope somebody can help.