Changing/Adding more than one email domain for customer companies

In the last few months we've had a number of customers change the associated email domain (companies had been sold or restructured). 

In order to migrate the existing emails to the new domain, we had to create a new company with the new correct domain and then move all the customers and emails manually over to that new domain. 

Also, some customers have more than one email domain (different endings, e.g. .org and .com, both are valid). 

At present it is not possible to have more than one email domain per company which causes issues in the two situations described above. Would it be possible to enable companies to have more than one email domain to solve that issue?