How to whitelist IP addresses on OpenVPN?

Question

VPN

Good day.
On stackoverflow and on Habré, quite detailed manuals were published by users on how to wrap only certain traffic on VPN, i.e. specific IPs and / or subnets go through the VPN, everything else works directly.
However, I can’t find a manual on how to solve the inverse problem, i.e. wrap all traffic in VPN, except for certain IPs and / or subnets.
At the moment I have an active subscription to one of the VPN service and Ubuntu 16.04 on the client.
Tell me in which direction to dig or what phrases to google to come to the solution of my problem. I will be especially grateful for links to manuals on my problem.