Help with mwan3

Hi there, I've installed and configured mwan3 with 3 WAN interfaces and configured a balanced policy as primary and is working great but, now I want to set a rule to access sites like youtube only from an specific WAN or "member". Is this possible?

Thanks for your help.

It's feasible if you mark the traffic for specific service on the client side with packet filter.
Otherwise most likely not, because modern web services are fragmented into multiple domains and use dynamic load-balancing, so you need a good DPI-analysis to perform the routing properly.