EdgeRouter X DHCP assign IP by port?

I'm currently using the EdgeRouter X in the WAN+2LAN2 configuration and would like to have a fixed IP address issued by the DHCP server based on the port. For example, eth1 would get 192.168.1.2, eth2 192.168.1.3 and so on. I see I can reserve static IPs by MAC address but for my purposes that would require editing the configuration for each deployment. Is there any way to do this? I've considered creating four DHCP servers, each with a range of 1 address, but I hope there's an easier way.

-Matt