MB Relationships display only post name

Hello, i'm creating relations programatically, there is a way to display only the values stored from db instead of all possible options inside the select?

So user can only view and sort order the relations from backend but cant create/view new one.

Actually i'm using MB_Relationships_API::add but this api can't sort/update the relations

I need some help to understand which part of code i need to change.