How does one edit reverse DNS entries on Mac OS X 10.9.1?

I've learned today that mail from outside my network is occationally being blocked. A helpful person pointed me to http://mxtoolbox.com where I was able to determines that some SMTP servers will block mail, because the reverse DNS entries do not match the domain mx record: mail.pediatricheartcenter.org. So the question then becomes, how do I fix that?

I have opened the server app, and there is a reverse zone mapping for 173.198.104.132 which points to mail.pediatricheartcenter.org. When I use nslookup, I get a correct mapping in both directions, until I use nslookup on an external DNS:

nslookup 173.198.104.132 209.18.47.61

Non-authoritative answer:
132.104.198.173.in-addr.arpa          name = rrcs-173-198-104-132.west.biz.rr.com.

When I use the nslookup and point it to an external DNS, I find that the publically available reverse entry points to rrcs-173-198-104-132.west.biz.rr.com.

How do I fix that so that all domain name searches for 173.198.104.132 point to mail.pediatricheartcenter.org?