@viragomann
In order not to be misunderstood, I'm talking about running two OpenVPN servers on a unique pfSense box. This one which has a static public IP.
For instance you run one OpenVPN server on port 1194 for the branches and a second one as site-to-site on port 1195 for the client in the main location.
Why didn't i think of this?! Didn't know, that this works that easy but it's a good point, thank you.