LaunchDaemons Starting Before IP Addresses Have Been Assigned

I’m working on an annoying problem with my Mac mini (running OS X 10.9). I have postfix and pfctl scheduled to load as system daemons using launchd, and they do so successfully. However, they do so between the Ethernet link going up and IP addresses being assigned. As a result, pfctl cannot properly resolve the self keyword and only adds the localhost equivalents to pf’s rule list. Similarly, postfix terminates because it cannot reach the network interface.

Reloading each daemon after IP addresses have been assigned corrects the problem until the next reboot. Is there a way to delay when these daemons start? My system log shows I would only need to delay them by 20 seconds, at most. For the record, I also had this problem on OS X 10.6, 10.7, and 10.8.