Different IP addresses for input and output

Hello,
I have a question about FortiGate 500. I have an OpenVPN server with a private IP address of 192.168.1.2. I have assigned this server a public address like 1.2.3.4 and my server uses this address to connect to the internet. Now I want to assign a public virtual IP address, such as 1.2.3.5, for users to connect to this server via the Internet.

Is it possible?

Thank you.