Bridge and virtual interface?

Question

linux

There is a gate on ubuntu server 16.04, on which there are 2 physical interfaces. On the inside there is a bridge, which combines the physical internal and virtual interfaces. Softether VPN comes out through Wirth. The task is to raise a virtual interface (or just an ip address) for the guest Wi-Fi network, so that it is separate from the bridge.

Answer 1

If you have a managed switch, add a tagged VLAN to the port and make the interface wean.
If not, and there is no desire either - we raise eth0: 1, and give it our ip address.
!! How correctly it will work with the bridge - I do not know.