The behavior you see is the way Yealink designed it (firmware & template combination).
We would recommend to look up Yealink's documentation on this, as this is not something that is controlled via 3CX.
Just keep in mind that if you need to modify the template to achieve this, your 3CX system will be in an unsupported state, and you might face issues going forward (both with firmware updates, template updates, and functionality)