There is a trick you could do to send a WoL packet to a separate IP on the sender network and modify it so it is repreated on the network of the machine you want to wake up.
I can't find docs on thisb on mobile, but can look for it later.
It can't work like a typical IP packet routing tho. I've only made it work with a VPN connection.
Another thing you can do is ssh to your router and send a WoL packet from there on the machine's LAN.