No, at least I don’t think so.
You can get where you need to go by using an ssh tunnel and a proxy, we do this all day long in support. Using a terminal program (PuTTY if you’re on windows), configure the session with a dynamic tunnel, then config your browser to proxy thru the SOCKS ssh tunnel. I dedicate Firefox for this purpose because it has the native ability to config a proxy, but there are browser plugins to easily toggle on/off. Once configured, you simply browse to the VPN IP of the devices, or any IP the PBX has direct access to.
edit: Thinking further, I may be wrong, if you have your VPN server configured with Gateway enabled and access to the VPN route, the PBX will route between different VPN IPs.