IP:Port REDIRECT problem

[Marcin Giedz <marcin.giedz@eulerhermes.pl>]

Hello,

I'd like to redirect one of my services from one public IP:port to other 
one:

Internet -----------> Public_IP 1.2.3.4:4000 GATEWAY1 Internal_IP 
192.168.49.1 <--------------> SERVICE SERVER (192.168.49.10), default 
GATEWAY1 <------------------> Internel_IP 192.168.49.2 GATEWAY2 
Public_IP 4.3.2.1:4000 ----------> Internet

As you can see default gateway for SERVICE SERVER is GATEWAY1. In 
GATEWAY1's iptables rules there is redirection rule for port 4000 to 
SERVICE SERVER:4000. In such configuration everything is OK, I can run 
service from Internet via GATEWAY1:4000. But I also want to run this 
services via GATEWAY2:4000. I tried redirection from GATEWAY2 to 
GATEWAY1 via public IPs but it doesn't work.

Is it possible to do it?

Thanks,
Marcin