Sorry, there is no way to show certain options and not others built into the plugin. There is however other ways to approach this that would allow you to use what you already have.
Really, most sites would create a default option of “not selected” of some kind of language that makes sense, that way the default can be sensible and show the user that it was not selected, instead of just being missing. For example, our skateboard site lets you add trucks and wheels and assembly to it. If you do not, we don’t just not show that field in the cart, we show like
Trucks and Wheels: None. Board only.
That way, it’s really clear to the user that the option selected is no-option, or not-selected.
If you need a custom development to extend our plugin to meet your needs, you can always use our Get a Quote page to get an estimate.