Ability to limit external request forms to certain email domains

Hi team, 

Not sure how feasible this is, but I'd like to share an issue that's been happening frequently in our organization. 

We run office visits to bring potential new and existing clients into our experience centres. As our process stands, we have an external request form asking key details of who is requesting to bring in said visitors, what is needed for the visit, and other key details. This form link is shared with people in our organization, and it's typically Sales who fills it out; the form is external because Sales is not in Wrike. 

We had a few instances where this link somehow got out and we've had people outside our organization use this form. There are links in the form to our intranet, for example, or to our room email addresses (that we use for booking), as well as other pieces of information that are not meant for anyone outside of our organization to have access to.

It would be great if there was a way to be able to limit external usage of these forms - by email domain or IP or any other way - to ensure that we can keep them "internal" to our colleagues only. 

Thanks!