61 Internal devices, same internal port, external port +1 each time.

I'm in the process of setting up NAT for 61 new devices that must be monitored externally. The INTERNAL port for most of these devices are 80, but the EXTERNAL port must be 1000, 1001, 1002, etc until they can each be reached. I have a XG310 (SFOS 16.05.4 MR-4).

Example:

External  IP:External Port -> Internal IP:Internal Port

64.64.64.64:1001 -> 10.1.1.100:80
64.64.64.64:1002 -> 10.1.1.101:80
64.64.64.64:1003 -> 10.1.1.101:80
...
64.64.64.64:1036 -> 10.1.1.101:80

Basically, I need each INTERNAL port 80 for each of these devices to be mapped to one external port. Is there a better way to accomplish this than setting up a rule for each one? They cannot be load balanced, and must predictably correspond to the same device for monitoring purposes. I really want to avoid adding 60+ new rules to my current 40+ firewall rules.

Thanks!