I have a primary fiber line that I use for VPN tunnels and Video Conferencing and other business critical services. We also have a 100/20 Comcast line for emergency fail over.
The reception in the building is terrible so I like to have a mobile SSID available for the employees to do WiFi calling or check their emails on their breaks. For this I use the Meraki DHCP and NAT settings on the SSID which gives the mobile devices a 10.0.0.0/8 IP.
I currently limit the bandwidth on the Mobile SSID but I would rather just send the traffic out the lower quality failover Comcast line. However, I am having a little trouble because my internal IPs are 10.0.x.x as well. I do not see a way to send traffic out an interface by VLAN or SSID.