Add option to control create item's behavior in the list

[thely]

In my use case, I have a multiselect field for searching employees by name. I'd like it to be possible to create a new one, but 99% of the time, my users will be searching through existing items instead.

Would it be possible to include an option that determines whether the typed entry is automatically the selected one when create is true? I'd rather the created option be selected if it's the only available option, rather than always be the selected option.