Autopopulate E-Mail field

Hi.

I have a question about the posibility to autopopulate the E-mail field from other form field ( FirstName.LastName.birthdate@noemail.com)

For exemple, Daniel.Laviolette.01-05-1987@noemail.com.

I want to do that because I'm working a lot with calendar. Often, I have to enter in the callendar appointent with people that didn't give their e-mails. In this case, no link can be mage between CRM and Callendar. If I can create automatically a fake e-mail adress (and configure Mailchimp to exclude all adress with this domain name) i'll be able to link callendar to their file.