Unfortunately mandrill does not provide the same type of customizable routing that Mailgun does. Specifically, the ability to set up a forwarding route so that

Unfortunately mandrill does not provide the same type of customizable routing that Mailgun does. Specifically, the ability to set up a forwarding route so that Mailgun handles all of the forwarding is the reason we selected them. To date I have yet to find another email provider that does this and provides API access and multi-domains support.