@Virgo 

No, one to many, 

I have one external ip address, and i want use a loopback with my ip adress to access my local server without use his local address

Example

With NAT one to many,

External ip : 92.100.200.300

Server 1 : 192.168.1.100

Server 2 : 192.168.1.101

My computer : 192.168.1.102

if i use 92.100.200.300:80 from my computer on local i access on server 1

if i use 92.100.200.300:8080 form my computer on local i acces on Server 2

but actually on ER605, i haven't this possibility

on meraki MX64, it work perfectly with nat ip 1:many

  @jGrundheber 

Are we sure this isn't a terminology problem?  That looks like normal NAT to me.  You are just nat'ing different ports to different internal IPs.

In the controller it is done via "Port Forwarding"

In the ER605 in standalone it is probably done via "Virtual Servers" under NAT.  Although, I have never tried that myself.

The difference is that the ER605 uses the IP address tied to the WAN interface so instead of saying that you want to NAT to 92.100.200.300 you select the WAN interface you want the NAT to happen on.