if example.com is a simple website with only one or two IP addresses, or all from a single range of IP addresses, then just create a static route to that/those IP address using wan2.
--> 192.0.2.12 , 192.0.2.14 , and 192.0.2.15
/ip route add dst=192.0.2.0/24 gateway=x.x.x.x
(x.x.x.x = wan2's default gateway)
If you're using PCC or load balancing with routing / connection marks, then you'll need to add this route once for each routing mark that you use, as well as once with no routing mark.
If you don't know what routing marks are, then you're not using them, so ignore that.