using wireless network for local devices and Ethernet for everything else

I have a MacBook Pro and I want to configure the Ethernet port for all access except the class C network that the wireless is connected to. My configuration for the Ethernet port is 192.168.1.50 255.255.255.0 gateway 192.168.1.1, the wireless is configured 192.168.15.131 255.255.255.0 gateway 192.168.15.1. The wireless is connecting to a different router than the .1 environment. The wireless router has 2 networks, 192.168.13.1 and 192.168.15.1. Both have access to the Internet. The wireless router connects the .13 network to the internet but the .15 network also has access thru the .13 network to the internet. The .1 network give me access to all of my local devices and is a 1Gb fibre connection. The wireless router also has a 1Gb fibre network. I can't use the wireless for everything as it is NOT my network, it belongs to my son but he has my xtool f1 Ultra in his garage connected to the .15 network. Any suggestions on configuration for my MacBook? MacBook is running Sequoia 15.1.1.