Multiusers. Possible or not possible?

[GorYa]

Is it possible to make the component so that the user fills out a form in one of the paragraphs could select multiple registered users by name or nickname, or email (to find, on the autocomplete if such a person is), or append an unregistered user. Currently, the existing item allows users to select a single user from the drop-down list, and does not allow the user to append if that is not on the list.If this is possible to tell me how to do it or email a link. In this form there is (in my case) a lot of positive moments.Thank you