Question on setting where a specific physical port should only look through the VPN?

Question

network hardware

Hello everyone, I ask for help, because I do not finish it at all.
There is an office where there are 2 cash registers and, in fact, an accountant-cashier is physically working.
One cash desk belongs to a legal entity, which in fact is located there, and the second cash desk belongs to another legal entity, where there is no accountant now and the accountant of the first legal entity helps with the cash desk, but in his office.
The second legal entity rents an office in a different physical location, with its white IP address, etc. It's Mikrotik with VPN.
Thesis - you can’t send checks of these two legal entities from the same IP address, so I messed up so that in front of the second cash desk there is a home Zyxel with a VPN corridor to the second office and the default route there. But that's wild in 2020.
Therefore, I ask for help - as a conceptual in Mikrotik to raise this matter?
Well, like, create a VPN connection, bind a port to this VPN, assign this port a route like "all requests to all networks must go through the gateway - IP received in that VPN."
PS I poked around for an hour, but did not take off. I'm not a networker myself, I just can set up Mikrotik for a home / small office.
In the first office, where the cash registers, there is RB2011UIAS-RM, there are free ports.

Answer 1

https://wiki.mikrotik.com/wiki/Policy_Base_Routing