How to work simultaneously in several VPN networks?

Question

VPN

The company is engaged in software maintenance. Employees of the company work by connecting via RDP to the servers of customers. In most cases, customers use vpn. Subnets can overlap.
As a result, employees have to install various vpn clients on their computers (cisco, openvpn, kerio, plus vpn using windows).
Two main problems:
1. It is impossible to work simultaneously with different customers (connect via RDP), because vpn clients can only work one by one.
2. From time to time there are failures between vpn-clients, when the installation of the next one breaks the performance of the already installed ones.
It is also important to transfer employees to work through an internal terminal server to preserve the working environment and the ability to work remotely.
Is it possible to organize work in such a way that employees go to their remote desktop on the company's server and from there already connect via RDP to customers without running vpn clients? Is it possible to set up one or more transit virtual machines that will hold vpn's?

Answer 1

We raise the server. We raise the VPN server on the server.
Using a firewall and / or VPN server, we specify rules like:
- connect to the address 1.2.3.4 port 1234 - map to the customer's subnet 1.
- connect to the address 4.3.2.1 port 4321 - map to the customer's subnet 2
, etc.

Answer 2

Plus the previous speaker. Select networks from a range that does not exactly intersect (from the range 10.0.0.0/24). And labeling packets, route by labels