Is it possible to make a node, which would provide vpn connections functionality? And more - multiple vpn connections, with ability to send defined packets to defined connection?
I don't know of any node that implements this kind of functionality. If you know how to write Java code, you might want to check out the Java Snippet node or even better, use the KNIME SDK to implement a native VPN Connector node. I know, this is not what you are looking for, I just want to give you some pointers.