Add new decision with custom type

When we add a new decision in a decision requirements diagram, we can choose the type between Literal Expressions and Decision Table, now we want to add a new type which is a special decision table with fixed outputs, may I know is there a way to do that?

So you want to create a DMN decision table that is read-only. The problem is that there is no option to make the decision table editor read-only in some cases and editable in others.