Migrating part of my domain's services to Heroku, part on my VPS

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http://serverfault.com – I have a virtual private server (VPS) with several services running on it -- most notably email and a Django web application with it's software stack (MySQL, Apache, etc.). The VPS has a domain name assigned to it and an SSL certificate for it's assigned IP address. I'd like to migrate the web application to Heroku using the same domain name. I'd like to leave the other services (email especially) hosted on my VPS. Is this possible? Can I have the web application hosted on Heroku at, say, mydomain.com and have other services like email for [email protected] for the same domain hosted on m (HowTos)