Remove field validation in a certain form?

I have the [email iframe-mail_owner id:iframe-mail_owner] field filled in automatically, via postmessage, I send several email addresses there at once, to which contact form 7 complains that my field is invalid. Is it possible to remove this field validation only in this form? Or how to make the [email iframe-mail_owner id:iframe-mail_owner] field work with a comma-separated list of email addresses?