Multi WAN route WireGuard via non default

[marcelmah]

Hi,

I am trying to setup an OPNsense 20.1.6 with multiple WAN links.
 - one is directly connected to the APU 4D4 with fixed IP and manually created gateway
 - second is a manually created gateway accessible via the LAN (this will eventually change to a direct connection to the fiber switch on a separate port on the APU 4D4)

I have WireGuard (road warrior) working if I use connection one as the default, but I want to use the second as the default and only use the first one for WireGuard traffic.

Can anyone help me how I can / should configure this, because I'm a bit lost...