@hamedfazel 

You have multiple public IP address. So you have used multiple WAN ports, or one WAN port has multiple public IP address?  If one WAN port has multiple public IP, did you achieve that with one to one NAT?

And do you mean to access your internal server from the public network? If yes and you use multiple WAN, then you can use Virtual Server to achieve your requirements. Just set two item for virtual server for each WAN port.