I have a new application Cisco expressway that recommends split DNS. To date we have had separate internal zone acme.local and external acme.com. I am resistant to split DNS because everything has worked fine as is for years. Cisco wants a record in acme.com that only resolves internally. How can I setup an internal acme.com zone without creating an entire copy of external acme.com with this extra record? I want to avoid managing acme.com in two places. Can I setup an internal acme.com that just resolves the one record but refers to outside DNS for all other acme.com resolution?